Apparatus and method for frequency shifting of a wireless signal and systems using frequency shifting

ABSTRACT

Network providing improved coverage based on a frequency shifting scheme. A wireless signal in a frequency band is shifted to another distinct band, and carried in the shifted band, using wired or wireless mediums, to another location, wherein the wireless signal is shifted back to the original frequency band. In one embodiment, the wireless signal is frequency shifted by converting it to other representing signals and forming the frequency-shifted signal from the representations. The medium may use dedicated wiring or existing service wiring in a residence or building, including LAN, telephone, AC power and CATV wiring. The system (in whole or in part) may be enclosed as a stand-alone unit, housed in integrated form as part of a service outlet or as a snap-on/plug-in module.

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of application Ser. No. 11/329,270, filed Jan.11, 2006, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to frequency shifting of asignal, and specifically the shifting of wireless signals. Moreparticularly, embodiments of the present invention relate to improvingthe coverage of wireless networks, using frequency shifted signals overnon-wired and wired mediums.

REFERENCES

The following documents are incorporated in their entirety for allpurposes as if fully set forth herein:

-   -   a. U.S. Pat. No. 6,862,353 to Rabenko, et al. entitled: “System        and Method for Providing Power over a Home Phone Line Network,”,        referred to herein as '353.    -   b. U.S. Patent Application Publication 2004/0151305 to Binder,        et al. entitled: “Method and System for Providing DC Power on        Local Telephone Lines”, referred to herein as '1305.    -   c. U.S. Patent Application Publication 2005/0010954 to Binder        entitled: “Modular Outlet”, referred to herein as '0954.    -   d. U.S. Patent Application Publication 2005/0180561 to Hazani,        et al. entitled: “Outlet Add-On module”, referred to herein as        '0561.    -   e. U.S. Patent Application Publication 2005/0249245 to Hazani,        et al. entitled: “System and Method for Carrying a Wireless        Based Signal over a Wiring”, referred to herein as '9245.    -   f. U.S. Pat. No. 6,842,459 to Binder entitled: “A network        Combining Wired and Non-Wired segments”, referred to herein as        '459.    -   g. U.S. Pat. No. 6,961,303 to Binder entitled: “Telephone        Communication System and Method over Local area Network wiring”,        referred to herein as '303.

BACKGROUND OF THE INVENTION

Frequency Shifting.

In many applications it is required to frequency shift a signal in thefrequency domain, as shown for example by graph 10 of FIG. 1. A firstsignal 11 is centered around frequency F2, and most of its energy isconcentrated between frequencies F1 and F3 along a frequency axis 13.Signal 12 is a frequency up-shifted replica of the first signal 11,centered around frequency F5 and residing between frequencies F4 and F6.With the exception of amplification and/or attenuation, the resultedshifted signal 12 is targeted to be a reliable replica of the firstsignal 11, substantially having the same characteristics, informationand frequency-response waveform, and occupying the same frequencybandwidth (i.e. F6−F4=F3−F1). The first signal 11 was up-shifted by ΔF,hence F5−F2=ΔF. Down frequency shifting of a signal is also known in theart, wherein the replica is shifted to a frequency spectrum lower thanthe original signal.

Frequency shifting devices are known in the art and commonly make use ofa mixer/filter arrangement (e.g. heterodyne). FIG. 2 is a block diagramillustrating a prior art heterodyne-based frequency shifter 20. Anoriginal (pre-shifting) signal (i.e. the first signal 11 of FIG. 1) isreceived via an input port 21, which may be a connector, and fed into amixer 22. The mixer 22 is also fed with a sine-wave signal having afrequency of F0 from a local oscillator 25. The mixer 22 is typically anonlinear circuit or device (such as a transistor or a mixer/Schottkydiode) having two input signals: The original signal from the input port21 and a local oscillator 25 signal are multiplied by the mixer 22. Onesignal at the output of the mixer 22 is equal in frequency to the sum ofthe frequencies of the input signal and another signal equal infrequency to the difference between the frequencies of the inputsignals; and (if not filtered out) also the original input signal. Inthe case of the first signal 11 being received in the input port 21, themixer 22 outputs will include the original first signal 11 shifted fromF2 to F2+F0 and also the original first signal 11 shifted from F2 toF2−F0. In the case wherein up frequency shifting is desired, a band passfilter (BPF) 23 filters out the lower frequencies (around F2−F0) andsubstantially passes the higher frequency band signal to the output port24; where the output port 24 may be a connector. In the case wherein thelocal oscillator frequency 25 is set to ΔF and the BPF 23 is designed tostop all frequencies other than frequencies between F4 to F6, thefrequency shifter 20 will output signal 12 upon input of signal 11 inport 21. While the above description refers only to frequency dependentpart of the frequency shifter 20, such frequency shifter 20 commonlyincludes many components involved in amplification, attenuation,limiting, and other functions that impact amplitude of the signals, buthave flat frequency response in the relevant frequency spectrum, andthus for simplicity sake are not described.

A super-heterodyne frequency shifter is known in the art for radioreceivers and other applications where a signal is required to besubstantially frequency shifted. Such a shifter involves two (or more)single heterodyne shifters connected in cascade. FIG. 3 is a blockdiagram illustrating a prior art shifter 30. The super-heterodyneshifter 30 shifts a signal input in the input port 21, and outputs theshifted signal via the output port 24 using two frequency-shiftingstages. The first stage contains a first mixer 22 a and a first localoscillator 25 a generating a reference signal having a frequency F10,and a first BPF 23 a connected to the first mixer 22 a output. Thesignal at the First BPF 23 a output serves as the input to the secondheterodyne stage containing a second mixer 22 b and a second localoscillator 25 b generating a reference signal having a frequency F11,and a second BPF 23 b connected to the output port 24. In such ashifter, the total frequency shifting will be the sum of both localsine-wave references F10+F11. Similarly, a super-heterodyne shifter maycomprise more than two stages, and may be used for up, as well as down,frequency shifting.

Implementing such a heterodyne, and even more, a super-heterodyneshifter requires many components, as described above. Suchimplementation commonly has a high part count, leading to high cost, aphysically large enclosure, added complexity, lower reliability andother disadvantages.

Wireless Home Networking.

A popular approach to home networking (as well as office and enterpriseenvironments) is communication via a radio frequency (RF) distributionsystem that transports RF signals throughout a building, to and fromdata devices. Commonly referred to as Wireless Local Area Network(WLAN), such communication makes use of the Industrial, scientific andMedical (ISM) frequency spectrum. In the United States, three of thebands within the ISM spectrum are the A band, 902-928 MHz; the B band,2.4-2.484 GHz (commonly referred to as 2.4 GHz); and the C band,5.725-5.875 GHz (commonly referred to as 5 GHz). Overlapping and/orsimilar bands are used in different regions such as Europe and Japan.

In order to allow interoperability between equipment manufactured bydifferent vendors, few WLAN standards have evolved, as part of the IEEE802.11 standard group, branded as WiFi (www.wi-fi.org). IEEE 802.11bdescribes a packet-based wireless communication using the 2.4 GHzfrequency band and supporting communication rate of 11 Mb/s, IEEE802.11a uses the 5 GHz frequency band to carry 54 MB/s and IEEE 802.11guses the 2.4 GHz band to support 54 Mb/s.

A node/client with a WLAN interface is commonly referred to as STA(Wireless Station/Wireless client). The STA functionality may beembedded as part of the data unit, or alternatively be a dedicated unit,referred to as a bridge, coupled to the data unit. While STAs maycommunicate without any additional hardware (i.e. ad-hoc mode), suchnetwork usually involves Wireless Access Point (e.g. WAP or AP) as amediation device. The WAP implements a Basic Stations Set (BSS) and/orad-hoc mode based on Independent BSS (IBSS). STA, client, bridge and WAPwill be collectively referred to hereon as a WLAN unit.

FIG. 5 is a graph 50 showing bandwidth allocation for IEEE802.11gwireless communication in the United States along frequency axis 59. Inorder to allow multiple communication sessions to take placesimultaneously, eleven overlapping channels are defined spaced 5 MHzapart, spanning from 2412 MHz as the center frequency for channel number1 (shown as 55), via channel 2 centered at 2417 MHz (shown as 56) and2457 MHz as the center frequency for channel number 10 (shown as 57), upto channel 11 centered at 2462 MHz (shown as 58). Each channel bandwidthis 22 MHz, symmetrically (+/−11 MHz) located around the centerfrequency.

FIG. 4 is a block diagram illustrating a WLAN unit block diagram 40. Forsake of simplicity, only IEEE802.11g will be described herein. Ingeneral, the wireless physical layer signal is handled in two stages. Ina transmission path, first the baseband signal (IF) is generated basedon data to be transmitted, using 256 QAM (Quadrature AmplitudeModulation) based OFDM (Orthogonal Frequency Division Multiplexing)modulation technique, resulting a 22 MHz (single channel wide) frequencyband signal. The signal is then up converted to the 2.4 GHz (RF), andplaced in the center frequency of a required channel, and transmitted tothe air via an antenna 52. Similarly, the receiving path comprises areceived channel in the RF spectrum, down converted to the basebandsignal (IF) wherein the data is then extracted.

The WLAN unit 40 connects to the wired medium via a wired port 41 (e.g.supporting IEEE802.3 10/100BaseT (Ethernet) interface). The physicallayer of this interface is handled by 10/100BaseT PHY function block 42,converting the incoming Manchester or MLT3 modulated signal(respectively according to the 10BaseT or 100BaseTX coding) into aserial digital stream. Similarly, a WLAN outgoing digital data stream ismodulated to the respective coded signal and transmitted via the wiredport 41, implementing full duplex communication. The internal digitalstream may be of proprietary nature of any standard one such as MII(Media Independent Interface). Such MII to Ethernet PHY 42 (i.e.Ethernet physical layer or Ethernet transceiver) can be implementedbased on “LAN83C180 10/100 Fast Ethernet PHY Transceiver” available fromSMSC—Standard Microsystems Corporation of Hauppauge, N.Y. U.S.A. Whilethis function can be implemented by using a single dedicated component,in many embodiments this function is integrated into single componentincluding other functions, such as handling higher layers. The PHY block42 also comprises isolation magnetic components (e.g.transformer-based), balancing, surge protection, and a connector(commonly RJ-45) required for providing a proper and standard interfacevia the wired port 41.

For the sake of simplicity, in the above description and hereon, only anEthernet 10/100BaseT interface will be described. However, it will beappreciated that any wired interface, being proprietary or standard,packet or synchronous, serial or parallel, may be equally used, such asIEEE1394, USB, PCI, PCMCIA, or IEEE1284, but not limited to.Furthermore, multiple such interfaces (being of the same type or mixed)may also be used.

In the case wherein the WLAN unit is integrated and physically enclosedwithin another unit (such as a data unit, e.g. computer) and does notsupport a dedicated and direct wired interface, part or all of thefunction of the PHY 42 may be obviated.

MAC (Media Access Control) and higher layers are handles in a MAC layerprocessor 43, comprising two sub blocks, designated as 10/100BaseT MAC53 and IEEE802.11g MAC 54. The 10/100BaseT MAC 53 handles the MAC layeraccording to IEEE802.3 MAC associated with the wired port 41. The10/100BaseT MAC 53 may be implemented using a “LAN91C111 10/100 Non-PCIEthernet Single Chip MAC+PHY” available from SMSC—Standard MicrosystemsCorporation of Hauppauge, N.Y. U.S.A, which includes both the10/100BaseT MAC 53 and the PHY 42 functionalities. Reference is made tothe data sheet of the manufacturer (Agere Systems product brief forWaveLAN™ 802.11a/b/g Chip Set and Agere Systems, WaveLAN™ WL60040Multimode Wireless LAN Media Access Controller (MAC), Product BriefAugust 2003 PB03-164WLAN). Similarly, the IEEE802.11 MAC 54 handles theMAC layer according to IEEE802.11g MAC associated with an antenna 52 (orother wireless port). Such IEEE802.11 MAC 54 is designed to supportmultiple data rates and encryption algorithms, and is commonly based onembedded processors and various memories. The IEEE802.11 MAC 54 may beimplemented using “WaveLAN™ WL60040 Multimode Wireless LAN media AccessController (MAC)” from Agere Systems of Allentown, Pa. U.S.A. All thebridging required in order to connect the wired IEEE802.3 MAC handled bythe 10/100BaseT MAC 53 to the wireless IEEE802.11g MAC 54 is alsoincluded in the MAC Layer Processor 43, allowing for integration andproper operation.

The data stream generated by the IEEE802.11g MAC 54 is converted to anOFDM-based baseband signal (and vice versa) by a baseband processor 48.In common applications, the baseband processor 48 (i.e. wireless modemand IF transceiver) is implemented by a transmitter/receiver 44digitally processing the data stream, and an OFDM unit (i.e. I-Qmodulator) 45 generating the actual signal. The communication channel inwireless environments imposes various impairments, such as attenuation,fading, multi-path, interferences, and many other impairments. Thebaseband processor 48 may process the data stream according to thefollowing functions:

-   -   a. Packet framing, wherein the data from the MAC 43 is adapted        and organized as packets, wherein header, CRC, preamble, control        information and end-of-frame delimiter are added;    -   b. Scrambler;    -   c. Convolution encoder (such as Viterbi encoder) to allow better        robustness against channel impairments such as impulse and burst        noise;    -   d. Puncturer to reduce the required data rate;    -   e. Interleaver performing permutations on the packet blocks        (e.g. bytes) in order to better immunize against error bursts by        spreading the information; and    -   f. IFFT (Inverse FFT) modulator to produce separate QAM        (Quadrature Amplitude Modulation) constellation sub-carriers.

Using digital to analog conversion, the processed digital data from thetransmitter portion of the transmitter/receiver 44 is used to generatethe OFDM baseband signal in the modulator 45. The received OFDM basebandsignal from functional block 46 is digitized by the modulator 45,processed by the receiver portion of the transmitter/receiver 44,transferred to the MAC Layer Processor 43 and PHY 42 to be transmittedvia the wired port 41. Some implementations of WLAN chipsets provide theactual baseband signal, while others provide orthogonal analog I/Q modemsignals which need to be further processed to provide the actual realanalog form IF (Intermediate Frequency) OFDM baseband signal. In such acase, as known in the art, a Local Oscillator (LO) determining the IFfrequency is used to generate a sinewave that is multiplied by the Isignal, added to the Q signal multiplied by 90 degrees shifted LOsignal, to produce the real analog IF baseband signal. The basebandprocessor 48 may be implemented based on “WaveLAN™ WL64040 MultimodeWireless LAN Baseband” from Agere Systems of Allentown, Pa. U.S.A.SA5250 Multi-Protocol Baseband from Philips Semiconductors includingboth baseband processor 48 and IEEE802.11 MAC 54 functionalities may bealternatively used.

The WLAN Transceiver (i.e. RF-IF Converter) 46 shifts the IF OFDMbaseband signal from the baseband to the ISM RF band. For example, anOFDM baseband signal symmetrically centered around 10 MHz and requiredto use channel 2 of FIG. 5, centered at 2417 MHz, is required to befrequency shifted by 2417−10=2407 MHz. Such frequency shifting may usemany methods known in the art. A direct modulation transmitter/receivermay be used for frequency shifting, as may be the case where “WaveLAN™WL64040 Dual-Band Wireless LAN Transceiver” from Agere Systems ofAllentown, Pa. U.S.A. is used to directly convert the orthogonal I-Qanalog signal to the 2.4 GHz RF band. Alternatively, superheterodyne(e.g. dual conversion) architecture may be used, as described for“SA5251 Multiband RF Transceiver” from Philips Semiconductors. The WLANTransceiver 46 and the baseband processor 48 compose the wireless pathphysical layer processor 47.

A T/R Switch 49 is used to connect the antenna 52 to the transmitterpath and disconnect the receiver path (to avoid receiver saturation)upon a control signal signaling transmission state of the WLAN unit 40.PIN Diode switch based design is commonly used, such as PIN Diode switchSWX-05 from MCE—KDI Integrated Products of Whippany, N.J., U.S.A. Theantenna 52 is coupled via a RF filter 51 in order to ensure transmittinglimited to the defined band mask (removing unwanted residual signals),and to filter out noise and out of band signal in the receiving mode.The RF filter 51 may use SAW (Surface Acoustic wave) technology, such asa “2441.8 MHz SAW Filter” from SAWTEK (A TriQuint company) of Orlando,Fla. U.S.A.

Actual implementation of the WLAN unit 40 may also involve amplifiers,attenuators, limiters, AGC (Automatic Gain Control), and similarcircuits involved with signal level functions. For example, a Low NoiseAmplifier (LNA) is commonly connected in the receive path near theantenna (a.k.a. aerial) 52. An example of LNA includes, but not limitedto, the “MAX2644 2.4 GHz SiGe, High IP3 Low-Noise Amplifier”. Similarly,a Power Amplifier (PA) may be used in the transmit path, such as the“MAX2247 Power Amplifier for IEEE802.11g WLAN”. Both the LNA and the PAare available, for example, from Maxim Integrated Products of Sunnyvale,Calif. U.S.A. For the sake of simplicity, such functions are omitted inFIG. 4 as well as in the rest of this document. Similarly, whereineither a transmitting or a receiving path is described in this document,it should be understood that the opposite path also exists forconfiguring the reciprocal path.

A non-limited example of a detailed block diagram of a typical physicallayer processor 47 is shown in FIG. 6, including a WLAN transceiver 46shown individually in FIG. 7. A WLAN transceiver 46 is based ondirect-conversion and low intermediate-frequency techniques known in theart, such as used in the “Dual-Band Wireless LAN Transceiver WaveLANWL54040” from Agere Systems Inc., shown as comprising I/Q modulator 67and I/Q de-modulator 68. The RF signal received in the antenna 52 isinput (via RF filter 51 and TX/RX Switch 49 as shown in FIG. 4) to theI/Q modulator 67 via port 61. The signal is fed into the two mixers 22 aand 22 b. Both mixers 22 a and 22 b are connected to a local oscillator25 based on a quartz crystal 64. The local oscillator 25 may comprise asynthesizer, a VCO (Voltage Controlled Oscillator), a PLL (Phase LockedLoop), and a NCO (Number Controlled Oscillator), as known in the art.The local oscillator 25 is directly fed to mixer 22 b. A sine-wavereference signal from the oscillator 25 is fed to the mixer 22 a via 90degrees phase shifter 63 a. In addition to the frequency down shifting,the I/Q modulation is obtained wherein the output signal (after properfiltering, not shown in the figure) from mixer 22 a is the Quadrature(Q) component over port 65 a and the output from mixer 22 b is theIn-phase (I) component over port 65 b of the received RF signal in port61. The I/Q demodulator 68 receives I/Q components of the signal to betransmitted via ports 66 b and 66 a respectively. The I and Q componentsignals are up-frequency shifted by mixers 22 c and 22 d respectively,wherein the mixer 22 d is directly fed from the oscillator 25, whilemixer 22 c is fed with a 90 degrees phase shifted signal through phaseshifter 63 b. The outputs of both mixers 22 c and 22 d are summed by anadder 76 and fed as the RF signal to be transmitted by the antenna 52(FIG. 4) via port 62. It will be appreciated that the WLAN transceiver46 further comprises filter, amplifiers, control, timing, and othercircuits not described above and omitted for clarity and simplicitysake. As described above, the inputs and outputs of the WLAN transceiverare of analog nature and are either low IF or RF based signals. Hence,most such WLAN transceivers are considered as analog parts and do notinclude substantial digital processing or digital circuitry.

A baseband processor 48 is typically a digital part including a DSP(Digital Signal Processor) and other digital circuits. In order to adaptbetween the digital baseband processor 48 and the analog signals to andfrom the WLAN transceiver 46, a converters set 31 between analog anddigital signals is included as the mixed signal part of the processor48. Analog to digital converters 69 a and 69 b respectively convert theQ and I signal components received respectively via ports 65 a and 65 b,to digital representations fed to the OFDM modulator 38. Similarly, thedigital Q and I components from the OFDM demodulator 37 are converted toanalog using respective digital to analog converters 32 a and 32 b. TheOFDM demodulator 38 and the OFDM modulator 37 are full digital circuits,commonly based on DSP (Digital Signal Processing).

After down frequency shifting and I/Q modulating (by IQ demodulator 67)and after being digitized by analog to digital converters 69 a and 69 b,the received WLAN signal is input to the OFDM modulator 38. Theprocessing in this block includes frequency handling 39, Fast FourierTransform (FFT) 71, de-mapper 72, and a descrambler, decoder (commonlyViterbi decoder), and de-interleaver as part of block 73. The modulatedsignal is output via port 74 to the MAC unit 43.

On the transmit path, data received from the MAC Layer Processor 43 viaport 75 is I/Q demodulated by the OFDM demodulator 37. The OFDMdemodulator 37 comprises, inter-alia, a scrambler, a coder (usuallyViterbi coder) and interleaver as part of block 36, feeding output datato a mapper 35, which in turn feeds to the IFFT unit 34. After cyclicextension 33, the created digital I/Q components are converted to analogby digital to analog converters 32 b and 32 a, respectively, and theanalog signals are respectively outputted to ports 66 b and 66 a of theWLAN transceiver 46. It will be appreciated that the baseband processor48 further comprises filters, amplifiers, control, timing, framing,synchronization, and other circuits not described above and omitted forclarity and simplicity sake.

Outlets

The term “outlet” herein denotes an electro-mechanical device thatfacilitates easy, rapid connection and disconnection of external devicesto and from wiring installed within a building. An outlet commonly has afixed connection to the wiring, and permits the easy connection ofexternal devices as desired, commonly by means of an integratedconnector in a faceplate. The outlet is normally mechanically attachedto, or mounted in, a_wall or similar surface. Non-limiting examples ofcommon outlets include: telephone outlets for connecting telephones andrelated devices; CATV outlets for connecting television sets, VCR's, andthe like; outlets used as part of LAN wiring (also referred to as“structured wiring”) and electrical outlets for connecting power toelectrical appliances. The term “wall” herein denotes any interior orexterior surface of a building, including, but not limited to, ceilingsand floors, in addition to vertical walls.

Wireless Coverage.

Most existing wireless technologies, such as IEEE802.11x (e.g.IEEE802.11a/g/b), BlueTooth™, UWB (Ultra Wide-Band) and others, arelimited to tens of meters in free line of sight environment. In commonbuilding environments, wherein walls and other obstacles are present,the range of wireless communication may be dramatically reduced. Assuch, in most cases a single wireless unit (such as an access point)cannot efficiently cover the whole premises. In order to improve thecoverage, multiple access points (or any other WLAN units) are commonlyused and distributed throughout the environment.

In order to allow the access points to interconnect in order to form asingle communication cluster in which all the WLAN units can communicatewith each other and/or with wired data units, a wired backbone iscommonly used, to which the access points are connected. Such a networkcombining wired and wireless segments is disclosed for example in U.S.Pat. No. 6,330,244 to Swartz et al. Such a configuration is populartoday in offices, businesses, enterprises, industrial facilities andother premises having a dedicated wiring network structure, commonlybased on Category 5 cabling (also referred to as structured wiring). Theaccess point devices interface the existing wiring based on local areanetwork (LAN), commonly by a standard data interface such as Ethernetbased 10/100BaseT.

As explained above, installing a dedicated network wiring infrastructurein existing houses is not practical. The prior art discloses usingexisting AC power wiring also as the wired backbone for interconnectingWLAN units. Examples of such prior art includes U.S. Pat. No. 6,535,110to Arora et al. U.S. Pat. No. 6,492,897 to Mowery, Jr., U.S. Patentapplication 2003/0224728 to Heinonen et al., and U.S. Pat. No. 6,653,932to Beamish et al. There are several drawbacks to using powerlines as abackbone for connecting WLAN units involves several drawbacks. The typeof wiring, noise, and the general hostile environment results in a poorand unreliable communication medium, providing low data rates andrequiring complex and expensive modems. In addition, the connection of aWLAN unit to the powerline requires both a wireless and a powerlinemodems for handling the physical layer over the two media involved, aswell as a complex MAC to bridge and handle the two distinct protocolsinvolved. As such, this solution is complex, expensive and offers lowreliability due to the amount of hardware required.

U.S. Patent Application '9245 suggests a system 80 including anapparatus 81 for bridging between a wireless link via antenna 52 and awired medium 83 connected via connector 82 as shown in FIG. 8. However,super-heterodyne scheme is suggested for frequency shifting the wirelesssignal in order to carry it over a wiring.

In consideration of the foregoing, it would be an advancement in the artto provide a method and system for frequency shifting of a signal, andin particular a wireless signal, in a simple, cost-effective, faithful,reliable, minimum parts count, minimum hardware, or using existing andavailable components.

Furthermore, it would be highly advantageous to have a method and systemfor enlarging the coverage of a wireless network, and in particular tobring the coverage to a specific required locations, in a simple,cost-effective, faithful, reliable, minimum parts count, minimumhardware, or using existing and available components.

Similarly, it would be highly advantageous to have a method and systemfor seamlessly interconnecting separated or isolated coverage areas, ina simple, cost-effective, faithful, reliable, minimum parts count,minimum hardware, or using existing and available components.

Furthermore, it would be highly advantageous to have a method and systemfor using a wireless signals, wireless technologies, and wirelesscomponents for wired communication.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a method and apparatus forfrequency shifting of a signal is described. The signal in a firstfrequency band is I/Q demodulated by an I/Q demodulator into its ‘I’ and‘Q’ components signals, which are modulated by an I/Q modulator toreconstruct the signal over a distinct and non-overlapping secondfrequency band. Similarly, additional set of an I/Q demodulator and anI/Q modulator may be used to frequency shift from the second frequencyband to the first frequency band, thus allowing for bi-directionalhalf-duplex or full-duplex paths. The signal may be a wireless signal,received and transmitted by two antennas, one for each frequency band.Alternatively, a single antenna may be used for both frequency bands.The frequency shifters in all above systems hereinafter may use anyfrequency-shifting scheme, such as mixer/filter, heterodyne orsuper-heterodyne, or using I/Q demodulating and modulating as describedabove.

In another aspect of the present invention, frequency shifting is usedin a wireless network for increasing the coverage and seamlesslybridging between two isolated or separated wireless coverage areas. Thenetwork is based on two frequency shifters, communicating with eachother over a first frequency band. Wireless signal from a first wirelessunit is received by one shifter and then frequency shifted to anotherfrequency band, and transmitted to the other shifter. The other shiftershifts the received signal to the original transmitted frequency bandand transmits to another wireless unit, being distant from the firstwireless unit, thus creating a wireless link between the two wirelessunits. The other direction is also operative for allowing half-duplex orbi-directional operation.

The communication between the frequency shifters above may also use twoadditional intermediate frequency shifters (or more), thus havingadditional frequency shifting to another distinct frequency band,allowing or additional increased reach and distance between the twowireless units.

In another aspect of the present invention, frequency shifting is usedin a wireless network for increasing the coverage and seamlesslybridging between two or more isolated or separated wireless coverageareas using an interconnecting wired medium. The network is based on twoor more frequency shifters, each covering a distinct area, communicatingwith each other over the wired medium. Wireless signal from a firstwireless unit is received by one shifter and then down frequency shiftedfor being carried over the wired medium, and transmitted to the othershifter. The other shifter shifts the received signal to the originaltransmitted frequency band and transmits to another wireless unit, beingdistant from the first wireless unit, thus creating a wireless linkbetween the two wireless units. The other direction is also operativefor allowing half-duplex or bi-directional operation.

Connecting the frequency shifters to the wired medium may make use of asuitable connector, as well as a protection circuitry for accommodatingtransients, over-voltage and lightning, and any other protection meansfor reducing or eliminating the damage from an unwanted signal over thewired medium. A band pass filter may also be used for passing only theshifted wireless signals, and rejecting or stopping other signals in thedescribed path. A transformer may be used for isolating and reducingcommon-mode interferences. Further a wiring driver and wiring receiversmay be used in order to transmit and receive the appropriate level ofsignal to and from the wired medium. Equalizer may also be used in orderto compensate for any frequency dependent characteristics of the wiredmedium.

In another aspect of the present invention, the wired mediumconcurrently carries a power signal, which may be AC or DC. The powersignal is carried over a frequency band distinct from the band used forcarrying the shifted wireless signal, using a set of low pass filter(for DC) or a band pass filter (for AC) for coupling the power signal toor from the wired medium, and high pass filter or band pass filter, aswarranted, for coupling the shifted wireless signal to and from thewired medium. The power signal may be inserted in one point andextracted in another point, which may be the same point used forconnecting a frequency shifter. The power signal carried over the wiredmedium may be used for powering any connected devices, as well aspowering part or all of a frequency shifter and any connected circuitry,using applicable power converter to adapt between the power signal leveland type to the voltages (commonly DC) required for the operation of theconnected hardware. In one aspect of the invention, the power carryingwired medium is electricity AC power wires, primarily installed fordistributing electricity power from a generation station 115V 60 Hz (inNorth America) in general and in a building in particular.

In another aspect of the present invention, the wired mediumconcurrently carries a non-power signal, which may be in analog ordigital forms. Similarly, a service signal such as analog telephone orCATV related signals may be concurrently carried using FDM. Connectingthe various signals to and from the wired medium involves using a set offilters, each allowing for passing or a distinct band of the appropriatesignal, and stopping other the signal sharing the wired medium. Theadded signal may be inserted in one point and extracted in anotherpoint, which may be the same point used for connecting a frequencyshifter. In another aspect of the present invention, power signalcarried in addition to the non-power signals described using a distinctfrequency band and coupled to or from the wired medium using theappropriate filter. The power signal may be used to power any deviceconnected to the wired medium.

In another aspect of the present invention, one or more frequencyshifters are conductively connected to a wireless unit (such as WAP),which may be forming an integral part such as integrating both into asingle enclosure. Alternatively, a frequency shifter and its connectedenvironment may be connectable as an external device to an existing oravailable wireless unit. The connecting to the wireless unit may bethrough an attenuator for adjusting the levels of the signal in thepath. A splitter may be added in between for sharing the conductive pathwith an antenna, thus retaining the through-the-air wirelesscommunication of the wireless unit. In a network employing plurality offrequency shifters over a wired medium, one or more may be conductivelycoupled to a wireless units, allowing wired only, wireless only or anycombination thereof for coupling to the wired medium.

In another aspect of the present invention, multiple distinct wiredmediums are employed. The data is shared among all the wired mediums byusing a single frequency shifter and a splitter. The splitter connectsto all the wired mediums thus all of them share the single frequencyshifter. This frequency shifter may be coupled wirelessly orconductively to a wireless unit as discussed hereinabove. The devicesconnected to the other end of each such wired medium can be as describedabove. Similar to the above, some or all the wired medium mayconcurrently carry power or other signals, using FDM, phantom channel,split-tap transformer or any other scheme described herein or known inthe art.

In another aspect of the present invention there is provided anapparatus for faithful frequency shifting of a first spread-spectrumsignal without any protocol conversion from a first frequency band to asecond frequency band distinct from the first frequency band, saidapparatus comprising: a first port for receiving the firstspread-spectrum signal in the first frequency band; a first I/Qdemodulator coupled to said first port to receive the firstspread-spectrum signal from said first port, for deriving the I and Qcomponent signals of the first spread spectrum signal; a first I/Qmodulator coupled to said first I/Q demodulator to receive the firstspread spectrum signal I and Q component signals, said first I/Qmodulator being operative to reconstruct first spread-spectrum signaland to frequency shift the first spread-spectrum signal to the secondfrequency band; and a second port coupled to said first I/Q modulator toreceive the frequency shifted signal from said first I/Q modulator, foroutputting the frequency shifted first spread spectrum signal in thesecond frequency band. The apparatus may further be operative forfaithful frequency shifting of a second spread-spectrum signal withoutany protocol conversion from the second frequency band to the firstdistinct frequency band, said apparatus further comprising: a third portfor receiving the second spread-spectrum signal in the second frequencyband; a second I/Q demodulator coupled to said third port to receive thesecond spread-spectrum signal from said third port, for deriving the Iand Q component signals of the second spread spectrum signal; a secondI/Q modulator coupled to said second I/Q demodulator to receive thesecond spread spectrum signal I and Q component signals, said second I/Qdemodulator being operative to reconstruct the second spread-spectrumsignal frequency shifted to the first frequency band; and a fourth portcoupled to said second I/Q modulator to receive the frequency shiftedsignal from said second I/Q modulator, for outputting the frequencyshifted second spread spectrum signal in the first frequency band.

In another aspect of the present invention there is provided a networkfor wireless communication of a first wireless signal carried in a firstfrequency band between first and second wireless units, said networkcomprising: a first frequency shifter for wireless communication of thefirst wireless signal with the first wireless unit, said first frequencyshifter being operative to frequency shift the first wireless signalbetween the first frequency band and a second frequency band distinctfrom the first frequency band; and a second frequency shifter forwireless communication of the first wireless signal with the secondwireless unit, said second frequency shifter being operative tofrequency shift said first wireless signal between said first frequencyband and said second frequency band.

In another aspect of the present invention there is provided anapparatus for frequency shifting without any protocol conversion betweena wireless signal in a wireless frequency band carried by a wirelessmedium and a wired signal in a wired frequency band carried by a wiredmedium, said apparatus comprising: an antenna for receiving andtransmitting the wireless signal;

a wiring connector for connecting to the wired medium; a down frequencyshifter for down frequency shifting a signal from the wireless frequencyband to the wired frequency band; an up frequency shifter for upfrequency shifting of a signal from the wired frequency band to thewireless frequency band; an RF switch coupled between said antenna, saiddown frequency shifter and said up frequency shifter, said RF switchhaving first and second states, wherein in the first state said antennais coupled to said down frequency shifter and in the second state saidantenna is coupled to said up frequency shifter; and a wired frequencyband switch coupled between said wiring connector, said down frequencyshifter and said up frequency shifter, said wired frequency band switchhaving first and second states, wherein in the first state said wiringconnector is coupled to said down frequency shifter and in the secondstate said connector is coupled to said up frequency shifter; whereinsaid apparatus is switchable into distinct first and second states,wherein in the first state of said apparatus, said RF switch is in itssaid first state and said wired frequency band switch is in its saidfirst state for receiving the wireless signal from the antenna, downfrequency shifting the wireless signal and transmitting the shiftedwireless signal to the wiring connector; and wherein in the second stateof said apparatus, said RF switch is in its said second state and saidwired frequency band switch is in its said second state for receivingthe frequency shifted wireless signal from said wiring connector, upfrequency shifting to reconstruct the wireless signal and transmittingthe wireless signal to the antenna. The apparatus may be furthercomprising: a first signal detector coupled to said wiring connector forsensing the presence of a signal in the wired frequency band; and asecond signal detector coupled to said antenna for sensing the presenceof a signal in the wireless frequency band; wherein said apparatus isoperative to shift to its said first state upon sensing the presence ofa signal in the wireless frequency band and to shift to its said secondstate upon sensing the presence of a signal in the wired frequency band.

In another aspect of the present invention there is provided a networkfor wireless communication of wireless signals among a plurality ofwireless units, the wireless signals being carried in a wirelessfrequency band, the wireless units being interconnected by a wiredmedium for carrying wired signals in a wired frequency band distinctfrom and lower in frequency than the wireless frequency band, saidnetwork comprising a plurality of frequency shifters each connected tothe wired medium, and said network having two distinct states, wherein:in the first state, one of said frequency shifters is operative towirelessly receive a first wireless signal from one of the wirelessunits, down frequency shift the received wireless signal to the wiredfrequency band, and couple the shifted wireless signal to the wiredmedium, while wherein all other frequency shifters receive the shiftedwireless signal from the wired medium, up frequency shift the receivedshifted wireless signal to the wireless frequency band to reconstructthe first wireless signal, and transmit the reconstructed first wirelesssignal; and in the second state, one of said frequency shifters isoperative to wirelessly receive a second wireless signal from a wirelessunit, down frequency shift the received wireless signal to the wiredfrequency band, and couple the shifted wireless signal to the wiredmedium, while all other frequency shifters receive the shifted wirelesssignal from the wired medium, up frequency shift the received shiftedwireless signal to the wireless frequency band to reconstruct the secondwireless signal, and transmit the reconstructed second wireless signal.

In another aspect of the present invention there is provided anapparatus for coupling a wireless signal to a plurality of wiredmediums, for use with a wireless unit having an antenna connector andoperative to receive and transmit the wireless signal in a wirelessfrequency band, and with a plurality of distinct wired mediums, eachoperative for conducting signals in a wired frequency band, saidapparatus comprising: a coaxial connector for connecting to the antennaconnector of the wireless unit for receiving and transmitting thewireless signal in the wireless frequency band; a plurality of wiringconnectors each for connecting to a distinct wired medium; a frequencyshifter connected for frequency shifting between the wireless frequencyband and the wired frequency band; an RF attenuator coupled between saidcoaxial connector and said frequency shifter for substantiallyattenuating the signal in the wireless frequency band; and a wired bandsplitter connected to said frequency shifter and having multiple ports,each port connected to a wiring connector, said splitter being operativeto share a signal in the wired frequency band with all devices connectedthereto. The apparatus may be further operative for wirelesscommunication with a second wireless unit, said apparatus furthercomprising: an antenna for receiving and transmitting the wirelesssignal in the wireless frequency band; and an RF splitter connectedbetween said antenna, said attenuator and said coaxial connectors.

In another aspect of the present invention there is provided a networkfor wireless communication of a wireless signal in a wireless frequencyband among a plurality of wireless units interconnected by a pluralityof distinct wired mediums, the wired mediums providing a wired frequencyband distinct from, and lower in frequency than, the wireless frequencyband, each wired medium having first and second ends, said networkcomprising: a center device coupled to a selected wireless unit andconnected to the first end of each of the wired mediums, said centerdevice being operative to frequency shift the wireless signal betweenthe wireless frequency band and the wired frequency band; and aplurality of remote devices, each connected to a second end of one of arespective one of the wired mediums and each coupled to a respectivewireless unit, each of said remote devices being operative to frequencyshift a signal between the wireless frequency band and the wiredfrequency band, wherein: said network is operative to the allow saidcenter device to receive the wireless signal in the wireless band fromthe selected wireless unit, to down frequency shift the wireless signalto the wired frequency band, and to transmit the shifted wireless signalto all connected wired mediums; each of said remote devices is operativeto up frequency shift shifted wireless signal from said center device tothe wireless frequency band, to reconstruct the wireless signal, and totransmit the reconstructed wireless signal to the respective wirelessunit; said network is operative to allow one of said remote devices toreceive a wireless signal in the wireless band from one of the wirelessunits coupled thereto, to down frequency shift the received wirelesssignal to the wired frequency band, and to transmit the shifted wirelesssignal to the connected wired medium; and said center device isoperative to up frequency shift the received shifted wireless signal tothe wireless frequency band to reconstruct the wireless signal, and totransmit the reconstructed first wireless signal to the coupled wirelessunit.

Each of the above frequency shifters may be unidirectional or allow forhalf-duplex or bi-directional operation, as well as full duplex. In suchconfiguration a threshold detectors are coupled to the receiving ports.The direction of the signal flow is dynamically determined by thenetwork flow. Upon sensing of the presence of a received signal in aport, the shifter is operative to receive the signal from this port(being antenna for wireless signal or connector for the wired medium)and transmit in the other port (being antenna for wireless signal orconnector for the wired medium).

In each of above mentioned frequency shifters, one or more of the I/Qmodulators and I/Q demodulators mentioned above may be part of awireless transceiver component commonly available in the market andcommonly used in wireless units. Each of the first (and second, whereapplicable) frequency bands may be selectable from a plurality ofpossible bands by a control port or a user settable mechanical switch.

The frequency shifters in all above systems may use anyfrequency-shifting scheme, such as mixer/filter, heterodyne orsuper-heterodyne, or using I/Q demodulating and modulating as describedabove.

Each of the signals above may be a spread-spectrum signal such asmulti-carrier (e.g. OFDM, DMT and CDMA), or a single carrier(narrow-band) signal. Each of the wireless signals or the wirelesscommunication links above may be WPAN, WLAN, WMAN, WAN, BWA, LMDS, MMDS,WiMAX, HIPERMAN, IEEE802.16, Bluetooth, IEEE802.15, IEEE802.11 (such asa, b and g), UWB, ZigBee and cellular such as GSM, GPRS, 2.5G, 3G, UMTS,DCS, PCS and CDMA. Similarly, each of the frequency bands above may bepart of the ISM frequency bands.

Wherein two distinct frequency bands are discussed above, twonon-overlapping channels being part of the same frequency allocatedstandard may be used.

Any of the above devices, sub-systems and systems, may be in full or inpart enclosed in a single enclose. The enclosure may be wall mounted,and may further be constructed to plug into an outlet. Furthermore, theenclosure may be mechanically attached (and detached) to an outlet. Theenclosure may also be shaped to substitute a standard outlet, and may beeither constructed to have a form substantially similar to that of astandard outlet, or as wall mounting elements substantially similar tothose of a standard wall outlet, or have a shape allowing directmounting in an outlet opening or cavity, or have a form to at least inpart substitute for a standard outlet.

Wired medium in any of the embodiment described may be any twoconductors or any two wires. In particular, the wired medium may be aUTP, STP, coaxial cable, a telephone wire pair, a CATV coaxial cable, ACpower wire pair and LAN cable such as Category 5 or category 6. Thewired medium may be outdoors, indoor or connecting there between, andmay be accessed via outlets in a building. A suitable connector may beused for connecting to the specific type of the wired medium, such ascoaxial connector for connecting to a coaxial cable and a telephoneconnector for connecting to a telephone wire pair. The wired medium maybe a single non-used twisted-pair in a LAN cable, or two such pairsconnected in parallel. In another aspect of the present invention, thewired medium is using a phantom channel formed between two wire pairs,such as two twisted wire pairs in a LAN cable used in Ethernet 10BaseT,100BaseTX or 100BaseT. Similarly, any PAN, LAN, MAN or WAN wiring may beused as the wired medium.

Furthermore, the topology of the wired medium may be a point-to-pointconnecting only two devices, one to each end, or may be any multi-pointtopology such as bus, ‘tree’, ‘star’ and point-to-multipoint.

Carrying DC power over the wired medium may use PoE scheme (such as perIEEE802.3af or IEEE802.3at) and components. Multiplexing DC power signalor any low frequency signal (such as POTS analog telephony) may make useof FDM as described or a split-tap transformer. Furthermore, the DCpower and POTS may be both simultaneously carried over the same twoconductors using non-DC related methods to carry the ‘On-Hook’ and‘Off-Hook’ signals, such as using tones.

In another aspect of the present invention, the phantom channel, beingpart of a LAN cable or otherwise, is used for carrying a wireless-basedsignal (such as UWB or shifted wireless signal) with or without thepower signal (such as PoE or AC power signal). Power and other signalsmay be carried over a single phantom channel using FDM.

In another aspect of the present invention, the non-conductive path ofone or more frequency shifters is not a radio-based wireless signalpropagated over the air. Instead, other non-conductive mediums may beconsidered such as fiber optic cable. Furthermore, the communicationthrough the air (consisting the non-conductive path) may use physicalphenomenon other than electromagnetic radio waves, such as light beingeither in visible or in the non-visible (e.g. IR and UV) spectrum, orusing acoustic waves, either in the audio/voice spectrum, ultrasound orinfrasound. In each case, the antenna and other related components aresubstituted with devices capable to either receive or transmit or bothusing the mentioned physical phenomenon. Similarly, the shifters andother connected equipment need to be replaced or adjusted to support therequired frequency band.

The systems and network according to the invention may be used outdoorsto allow increased free-air propagation coverage, or may be used indoorsto allow wireless communication between rooms and floors in a building.Similarly, the arrangements may allow for communication betweenbuildings. Furthermore, the methods described may be used to allowbridging between outdoor and indoor communication. Furthermore, awireless signal may be transported over the wireless or wired mediumserving as a backbone between locations using the same frequency bandhence faithfully restoring the wireless signal in full or the system maybe used to frequency shift the wireless signal between the remotelocations.

The above summary is not an exhaustive list of all aspects of thepresent invention. Indeed, the inventor contemplates that his inventionincludes all systems and methods that can be practiced from all suitablecombinations and derivatives of the various aspects summarized above, aswell as those disclosed in the detailed description below andparticularly pointed out in the claims filed with the application. Suchcombinations have particular advantages not specifically recited in theabove summary.

It is understood that other embodiments of the present invention willbecome readily apparent to those skilled in the art from the followingdetailed description, wherein are shown and described only embodimentsof the invention by way of illustration. As will be realized, theinvention is capable of other and different embodiments and its severaldetails are capable of modification in various other respects, allwithout departing from the scope of the present invention as defined bythe claims. Accordingly, the drawings and detailed description are to beregarded as illustrative in nature and not as restrictive.

The above and other features and advantages of the present inventionwill become more fully apparent from the following description, drawingsand appended claims, or may be leaned by the practice of the inventionas set forth hereinafter. It is intended that all such additionalapparatus and advantages be included within this description, be withinthe scope of the present inventions and be protected by the accompanyingclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the manner in which the above recited and other advantagesand features of the invention are obtained, a more particulardescription of the invention briefly described above will be rendered byreference to specific embodiments thereof, which are illustrated in theappended figures and drawings. The invention is herein described, by wayof non-limiting example only, with reference to the accompanying figuresand drawings, wherein like designations denote like elements.Understanding that these drawings only provide information concerningtypical embodiments of the invention and are not therefore to beconsidered limiting of its scope.

FIG. 1 illustrates schematically the frequency spectrum of an arbitrarysignal and its frequency-shifted replica;

FIG. 2 illustrates schematically a simplified general functional blockdiagram of a prior art frequency shifter;

FIG. 3 illustrates schematically a simplified general functional blockdiagram of a prior art super-heterodyne frequency shifter;

FIG. 4 illustrates schematically a simplified general functional blockdiagram of a prior art WLAN unit;

FIG. 5 is a graph that illustrates schematically prior-art frequencyspectrum allocations of channels according to the IEEE802.11g standard;

FIG. 6 illustrates schematically a simplified general functional blockdiagram of a prior art spread-spectrum OFDM modem using I/Q signalrepresentations;

FIG. 7 illustrates schematically a simplified general functional blockdiagram of a prior art WLAN transceiver;

FIG. 8 illustrates schematically a simplified general diagram of a priorart WLAN wireless/wired bridging using frequency shifting;

FIG. 9 illustrates schematically a simplified general functional blockdiagram of a frequency shifter based on back-to-back connection of twoWLAN units according to the invention;

FIG. 10 illustrates schematically a simplified general functional blockdiagram of a frequency shifter according to the invention;

FIG. 11 illustrates schematically a simplified general functional blockdiagram of a unidirectional frequency shifter according to theinvention;

FIG. 12 illustrates schematically a simplified general functional blockdiagram of a bi-directional frequency shifter according to theinvention;

FIGS. 13 a, 13 b and 13 c illustrate schematically a simplified generalfunctional block diagram of frequency shifters according to theinvention;

FIG. 14 illustrates schematically a simplified general functional flowchart of a frequency shifter control according to the invention;

FIG. 15 illustrates schematically a simplified increased coveragegeneral network using a frequency shifter according to the invention;

FIG. 16 illustrates schematically a simplified general increasedcoverage network using multiple frequency shifters according to theinvention;

FIG. 17 illustrates schematically a simplified general network includingtwo buildings and using two frequency shifters according to theinvention;

FIG. 18 illustrates schematically a simplified general increased in-doorcoverage network using a frequency shifter according to the invention;

FIGS. 19 a, 19 b and 19 c pictorially illustrate various perspectiveviews of an exemplary AC power outlet plug-in unit using a frequencyshifter according to the invention;

FIGS. 19 d and 19 e pictorially illustrate various views of an exemplaryLAN outlet plug-in unit using a frequency shifter according to theinvention;

FIG. 20 illustrates schematically a simplified general prior-art networkincluding wired and wireless communication;

FIG. 21 illustrates schematically a simplified general functional blockdiagram of a frequency shifter used between wired and wireless linksaccording to the invention;

FIG. 22 illustrates schematically a simplified general network overpoint-to-point wiring using a frequency shifter according to theinvention;

FIG. 23 illustrates schematically a simplified general network overmulti-point wiring using a frequency shifter according to the invention;

FIG. 24 illustrates schematically a simplified general network overpoint-to-point wiring supporting remote powering and using a frequencyshifter according to the invention;

FIG. 24 a illustrates schematically a simplified general network over‘star’ topology wiring supporting remote powering and using a frequencyshifter according to the invention;

FIG. 25 illustrates schematically a simplified general network allowingdistant coverage area using a frequency shifter according to theinvention;

FIG. 26 illustrates schematically a simplified general functional blockdiagram of a WLAN unit based frequency shifter according to theinvention;

FIG. 27 illustrates schematically a simplified general increasedcoverage network supporting remote powering and using a frequencyshifter according to the invention;

FIG. 27 a illustrates schematically a simplified general increasedcoverage network supporting remote powering and using a frequencyshifter according to the invention;

FIG. 27 b illustrates schematically a simplified general networksupporting remote powering using split-tap transformer and using afrequency shifter according to the invention;

FIG. 28 illustrates schematically a simplified general increasedcoverage network supporting improved remote powering and using afrequency shifter according to the invention;

FIG. 29 illustrates schematically a simplified general networksupporting remote powering over multiple wire pairs using a RF splitteraccording to the invention;

FIG. 30 illustrates schematically a simplified general networksupporting remote powering over multiple wire pairs using alow-frequency splitter according to the invention;

FIG. 31 illustrates schematically a simplified general prior-art LocalArea Network;

FIGS. 32 and 32 a illustrate schematically a simplified general networksover LAN wiring according to the invention;

FIG. 33 illustrates schematically a simplified general network over LANwiring using phantom path according to the invention;

FIG. 34 illustrates schematically a simplified general prior-arthot-spot arrangement using a telephone wire-pair;

FIGS. 35 a and 35 b illustrate schematically simplified generalhot-spots networks supporting remote powering according to theinvention;

FIG. 36 illustrates schematically a simplified general increased in-doorcoverage network according to the invention;

FIGS. 37 a, 37 b, and 37 c pictorially illustrate various views of anexemplary AC power outlet plug-in unit using a frequency shifteraccording to the invention;

FIGS. 37 d, 37 e, and 37 f pictorially illustrate various views of anexemplary LAN outlet plug-in unit using a frequency shifter according tothe invention;

FIG. 38 illustrates schematically a simplified general network over atelephone wire pair according to the invention;

FIG. 39 illustrates schematically frequency spectrum allocations over atelephone wire-pair according to the invention;

FIG. 40 illustrates schematically a simplified general network providedover multiple telephone wire pairs according to the invention;

FIG. 41 illustrates schematically a simplified general wired andwireless network provided over a telephone wire pair according to theinvention;

FIG. 41 a illustrates schematically a simplified general wired onlynetwork provided over a telephone wire pair according to the invention;

FIG. 42 illustrates schematically a simplified general network providedover a telephone wire pair using split center-tap transformer accordingto the invention;

FIG. 43 illustrates schematically a simplified general network providedover multiple telephone wire pairs using RF splitter according to theinvention;

FIG. 44 illustrates schematically a simplified general increasedcoverage network provided over multiple telephone wire pairs using alow-frequency splitter according to the invention;

FIG. 45 illustrates schematically an arrangement for carrying power overa telephone wire pair according to the invention;

FIG. 46 illustrates schematically a simplified general network carryingpower, telephone and data over a telephone wire pair according to theinvention;

FIG. 47 illustrates schematically a simplified general hot-spot networkprovided over a telephone wire pair according to the invention;

FIGS. 48 a, 48 b and 48 c illustrate pictorially and schematicallysimplified general networks provided over a telephone wire pair in abuilding according to the invention;

FIGS. 49, 49 a and 49 b illustrate schematically simplified generalfunctional block diagrams of devices employing a frequency shiftersaccording to the invention;

FIGS. 50 a and 50 b illustrate schematically simplified generalfunctional block diagrams of frequency shifters using a DC poweringscheme according to the invention;

FIG. 51 illustrates schematically a simplified general network using DCpowering provided over a telephone wire pair according to the invention;

FIG. 52 illustrates schematically a simplified general network providedover multiple telephone wire pairs using an AC powering scheme accordingto the invention;

FIG. 53 illustrates schematically a simplified general network providedover multiple telephone wire pairs using a DC powering scheme accordingto the invention;

FIGS. 54 a and 54 b pictorially illustrate various views of an exemplarytelephone outlet plug-in unit using a frequency shifter according to theinvention;

FIG. 55 illustrates schematically the prior-art frequency spectrumallocations in a CATV system;

FIG. 56 illustrates schematically a simplified general network providedover a CATV coaxial cable according to the invention;

FIG. 57 illustrates schematically a simplified general network providedover an AC power wire pair according to the invention;

FIG. 58 illustrates schematically a simplified general network providedover multiple AC power wire pairs according to the invention;

FIG. 59 illustrates schematically a simplified general wired andwireless network provided over an AC power wire pair according to theinvention;

FIG. 60 illustrates schematically a simplified general wired onlynetwork provided over an AC power wire pair according to the invention;and

FIGS. 61 a, 61 b and 61 c pictorially illustrate various views of anexemplary AC power outlet plug-in unit using a frequency shifteraccording to the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

The principles and operation of a network according to the presentinvention may be understood with reference to the figures and theaccompanying description wherein similar components appearing indifferent figures are denoted by identical reference numerals. Thedrawings and descriptions are conceptual only. In actual practice, asingle component can implement one or more functions; alternatively,each function can be implemented by a plurality of components andcircuits. In the figures and descriptions, identical reference numeralsindicate those components that are common to different embodiments orconfigurations. Identical numerical references (even in the case ofusing different suffix, such as 45 a, 45 b and 45 c) refer to functionsor actual devices which are either identical, substantially similar orhaving similar functionality). It will be readily understood that thecomponents of the present invention, as generally described andillustrated in the figures herein, could be arranged and designed in awide variety of different configurations. Thus, the following moredetailed description of the embodiments of the apparatus, system, andmethod of the present invention, as represented in the figures herein,is not intended to limit the scope of the invention, as claimed, but ismerely representative of embodiments of the invention.

Wireless to Wireless Frequency Shifting.

According to one embodiment of the invention, a signal is shiftedbetween IEEE802.11g channels. System 90 in FIG. 9 shows a typical systemfor shifting signal between channels, for a non-limiting example betweennon-overlapping channels 1 and 11 (similar to FIG. 5 above). System 90is based on ‘back-to-back’ connection of two WLAN units 40 a and 40 b.WLAN unit 40 b includes an antenna 52 b, and is tuned to use channel 11.Digital data stream received in port 41 b (which may be EthernetIEEE802.3 10/100BaseT, for example), are converted into a radio-signalemploying channel 11 per the IEEE 802.11g standard, and vice versa.Similarly, WLAN unit 40 a converts between digital data signal at port41 a and radio signals available at antenna 52 a using channel 1. Thetwo digital data ports 41 a and 41 b are connected to each other, suchthat data received from the antenna 52 a in channel 1 are converted to adigital data stream available in port 41 a, fed to port 41 b overconnection 91, and then re-converted into a radio signal per theIEEE802.11g standard over channel 11. The reverse direction is operativeas well, wherein data received over channel 1 at antenna 52 b isconverted into a digital signal by WLAN unit 40 b and outputted by port41 b, then fed into port 41 a via connection 91, and converted intoradio signals using channel 11 by WLAN unit 40 a. Hence, the system 90basically shifts signals between channels 1 and 11, substantiallywithout changing the data carried over these channels, hence performinga signal frequency (channel) shifting.

System 90 shown in FIG. 9 employs two complete WLAN units 40 a and 40 b.As such, this solution is expensive, power consuming and bulky. Inaddition, the digital processing executed in a baseband processor and aMAC processor of each of the WLAN units 40 a and 40 b introducesubstantial latency to the system 90, causing a received signal to betransmitted after a delay. Such delay may be harmful tolatency-sensitive applications such as gaming, wherein interactivity isrequired, or in the case of multimedia streaming, such as audio orvideo. In particular, such latency may be detrimental in the growingVoIP over WiFi applications.

According to an embodiment of the invention, a signal is shifted betweenIEEE802.11g channels using an heterodyne frequency shifter 30 a as shownin FIG. 10. System 100 shown includes two antennas 52 a and 52 b, andheterodyne based frequency shifter 30 a including a mixer/filter and maybe implemented similar to heterodyne system 20 or super-heterodynesystem 30 as described above in accordance with the prior art. However,since the frequency shifting is relatively small relative to thefrequency of the channel, such implementation requires the use ofcomplex, high components count super-heterodyne technique, furtherinvolving accurate and expensive filters, and stable and accuratefrequency sources.

According to an embodiment of the invention, a radio signal is shiftedfrom one channel to another using I/Q representation of the radiosignal. A signal in a specific channel is demodulated to obtain I/Qcomponents of the signal, which are relatively low frequency signals.These I/Q components are then fed to an I/Q modulator, to reconstruct aradio signal, using a distinct channel.

Such a system is exampled as frequency/channel shifting system 110 inFIG. 11, wherein a signal is received in antenna 52 a, in channel 11 andthe system 110 shifts the signal to channel 1 as the output from antenna52 b. The received channel 11 radio signal is received by the antenna 52a, filtered by RF filter 51 a and fed to port 61 a of WLAN receiver 112.The WLAN receiver 112 includes an I/Q demodulator 67 a, which uses as afrequency reference source 25 a, stabilized by a crystal 64 a. Thefrequency reference source 25 a is controlled by a control unit 111,which is connected thereto via a frequency control port 79 a. Thecontrol unit 111 sets the frequency reference source 25 a (via port 79a) to a specific channel. In the exampled case wherein the channel 11carries the signal that is of interest, the control unit 111 setsappropriately the WLAN receiver 112 to process that channel. The I/Qdemodulator 67 a, thus processes the selected channel and respectivelyoutputs the ‘Q’ component to port 65 aa and the ‘I’ component to port 65ba.

The I/Q component signals are fed into WLAN transmitter 113 includingI/Q modulator 68 b. The I/Q modulator 68 b uses frequency source unit 25b stabilized by crystal 64 b. The frequency reference source 25 b is setby control unit 111 via port 79 b to select a specific channel. In thenon-limiting example, control unit 111 sets the reference source 25 b tochannel 1. The I/Q modulator 68 b receives the Q and I components viaports 66 ab and 66 bb respectively. The modulator 68 b then reconstructthe received radio signal (which was received by antenna 52 a) overchannel 1, and feed it to the RF filter 51 b via port 62 b. The radiosignal is then transmitted to the air by antenna 52 b. Hence, any signalreceived in channel 11 in antenna 52 a will be transmitted as channel 1from antenna 52 b. Thus, the above operation of system 110 can besummarized as involving the following steps:

a. Setting channel 11 as the receiving channel.

b. Demodulating the signal received in channel 11 into its baseband I/Qcomponent signals.

c. Setting channel 1 as the transmitting channel.

d. Re-Modulating the received baseband I/Q component signals into thesignal to be transmitted over channel 1.

The system 110 shown in FIG. 11 is unidirectional, supporting only ‘oneway’ signal path flow from the receiving antenna 52 a, through I/Qdemodulator 67 a, and via I/Q modulator 68 b to transmitting antenna 52b. However, most networks nowadays are required to be bi-directional. Abi-directional frequency/channel shifter 120 is shown is FIG. 12. Ingeneral, two similar sub-systems A (right side of the figure) and B(left side of the figure) are shown connected in a ‘back to back’configuration, wherein each sub-system includes a WLAN transceiver 46,TX/RX switch 49, RF Filter 51 and antenna 52. System 120 allows for afirst to signal path from antenna 52 a (channel 11) to antenna 52 b(channel 1), and a second reciprocal path from antenna 52 b (channel 1)to antenna 52 a (channel 11), as will be now described.

Similar to the above description, control unit 111 of system 120 in FIG.12 sets the appropriate channels to both A and B sub-systems. I/QDemodulator 67 a and I/Q modulator 68 a are both part of WLANtransceiver 46 a and both use frequency source 25 a, based on crystal 64a, and are channel controlled by the control block 111 via port 79 a.Similarly, I/Q Demodulator 67 b and I/Q modulator 68 b are both part ofWLAN transceiver 46 b and both use frequency source 25 b, based oncrystal 64 b, and channel controlled by the control block 111 via port79 b. In the non-limiting example of shifting between channels 1 and 11,the control 111 sets the WLAN transceivers 46 a and 46 b to channels 11and 1 respectively.

Referring to FIG. 12, the first signal path involves shifting fromchannel 11 received in antenna 52 a to channel 1 transmitted on antenna52 b. Similar to system 110 described above, the signal received inantenna 52 a is filtered by RF Filter 51 a, and fed via the TX/RX switch49 a to port 61 a of WLAN transceiver 46 a. I/Q demodulator 67 aprovides the I/Q component signals, respectively outputted to ports 65ba and 65 aa. The I/Q modulator 68 b, being part of WLAN transceiver 46b, receives the I and Q component signals respectively via ports 66 bband 66 ab, and reconstructs a radio signal over channel 1 which istransmitted through port 62 b. The radio signal is routed by the TX/RXswitch 49 b to the antenna 52 b via RF filter 51 b.

In the reciprocal path, the second signal path involves shifting fromchannel 1 received in antenna 52 b to channel 11 transmitted on antenna52 a. Similar to system 110 described above, the signal received inantenna 52 b is filtered by RF filter 51 b, and fed via the TX/RX switch49 b to port 61 b of WLAN transceiver 46 b. I/Q demodulator 67 bprovides the I/Q component signals, respectively outputted to ports 65bb and 65 ab. The I/Q modulator 68 a, being part of WLAN transceiver 46a, receives the I and Q component signals respectively via ports 66 baand 66 aa, and reconstructs a radio signal over channel 11 which istransmitted through port 62 a. The radio signal is routed by the TX/RXswitch 49 a to the antenna 52 a via RF filter 51 a.

Since by its nature the radio medium is ‘half duplex’ wherein only asingle transmitter is allowed, system 120 shown in FIG. 12 has one ofthe signal paths operative at a time. For example, two states may beprovided, wherein in a first state a packet may be shifted from channel11 to channel 1, and wherein in a second state the consecutive packetwill be shifted from channel 1 to channel 11. System 130 shown in FIG.13 further shows the elements in control of the frequency shifter 120states.

The channels to and from the wireless signal is shifted may be fixed inthe system, and may not be selected by a user or installer. However, itis preferred that the channels involved in frequency shifter 120 may beset during installation, configuration, and maintenance. In oneembodiment according to the invention, the channels are selected by auser or an installer using mechanical setting of two mechanical switches139 a and 139 b, which are respectively controlling the channelselection for sub-systems ‘A’ and ‘B’. The switches may be set to any ofthe operative 11 channels in IEEE802.11g, and are coupled to the controlunit 111, which reads the status of the switches and accordinglyconfigures the WLAN transceivers 46 a and 46 b. In addition to system120, Band Pass Filter (BPF) 131 a is shown connected to detector block(DET) 132 a. The BPF 131 a is connected in parallel to the path of thesignal received from the antenna 52 a, and passes only channel 1. Thesignal level in channel 1 is checked by DET 132 a, typically based on alevel threshold detector. Upon sensing a signal presence in channel 1,DET 132 a notifies the control unit 111 via connection 134 a. Similarly,The BPF 131 b is connected in parallel to the path of the signalreceived from the antenna 52 b, and passes only channel 11. The signallevel in channel 11 is checked by DET 132 b, typically based on a levelthreshold detector 134 b. Upon sensing a signal presence in channel 11,DET 132 b notifies the control unit 111 via connection 134 b. Whileshown in system 130 that the received signal level is measured after theRF filter 51 and before the TX/RX switch 49, other embodiment may useconnection at other points along the signal path, such as at the I/Q 65a and 65 b ports. In addition, signal presence detection may use morecomplex mechanisms other than simple threshold crossing.

In addition to the former described functionalities of control unit 111,the control unit 111 is also connected to control TX/RX switches 49 aand 49 b, using respective connections 133 a and 133 b. Each such TX/RXswitch 49 is operative to have two distinct states; in a ‘receive’state, a signal arriving from antenna 52 a is routed to port 61 of WLANtransceiver 46; and in a ‘transmit’ state, a signal to be transmitted atport 62 of WLAN transceiver 46 is routed to the antenna 52. Typicallyand as a default, the TX/RX switch 49 is in a ‘receive’ state unlesscommanded otherwise.

Upon sensing a signal in channel 1 in antenna 52 a by DET 132 a, thecontrol unit 111 sets TX/RX switch 49 b to shift to a ‘transmit’ state.TX/RX switch 49 a remains in its ‘receive’ state. Thus, a path of asignal from antenna 52 a to antenna 52 b is established. Similarly, uponsensing a signal in channel 11 in antenna 52 b by DET 132 b, the controlblock 111 sets TX/RX switch 49 a to shift to a ‘transmit’ state. TX/RXswitch 49 b remains in its ‘receive’ state. Thus, a path of a signalfrom antenna 52 b to antenna 52 a is established.

A flow chart 140, functionality of which is to be executed by thecontrol unit 111 as part of the operation of the system 130 is shown inFIG. 14. In this regard, and with regard to all flowcharts, each blockrepresents a module, step, segment, or portion of code, which comprisesone or more executable instructions for implementing the specifiedfunctionality. It should also be noted that in some alternateimplementations, the functions noted in the blocks may be occur out ofthe order noted in the figures. Upon power up (or following start uproutine such as self test) the control unit 111 starts with block 141.As is shown by block 141 TX/RX Switches 49 a and 49 b are set to normal‘receive’ state, wherein no signal is transmitted to the air. As isshown by block 142 a, the channel of sub-system A is set, by setting theWLAN transceiver 46 a via port 79 a, for example based on the reading ofswitch 139 a. As is shown by block 142 b, the channel of sub-system B isset, by setting the WLAN transceiver 46 b via port 79 b, for examplebased on the reading of switch 139 b. In the above non-limiting example,WLAN transceiver 46 a will be set to channel 1, while WLAN transceiver46 b will be set to channel 11. As is shown by block 143 a, connection134 a is checked in order to sense presence of a received signal in theselected channel in sub-system A. In the case such a signal is indeeddetected, control unit 111 instructs TX/RX switch 49 b to ‘transmit’state (block 144 a). As long as there is a signal present in antenna 52a (in the appropriate channel), the system will remain in this state(block 145 a).

Upon sensing loss of signal, TX/RX switch 49 b will resume to ‘receive’state (block 146 a) and the system will resume idle state until a signalis detected in either A or B sub-systems. Similarly, in step 143 b,connection 134 b is checked in order to sense presence of a receivedsignal in the selected channel in sub-system B. In the case such asignal is indeed detected, control unit 111 instructs TX/RX switch 49 ato enter a ‘transmit’ state (block 144 b). As long as there is a signalpresent in antenna 52 b (in the appropriate channel), the system willremain in this state (block 145 b). Upon sensing loss of signal, TX/RXswitch 49 a will resume to ‘receive’ state (block 146 b) and the systemwill resume idle state until a signal is detected in either A or Bsub-systems.

The control unit 111 may be based on a discrete logic or an integrateddevice, such as a processor, microprocessor or microcomputer, and mayinclude a general-purpose device or may be a special purpose processingdevice, such as an ASIC, PAL, PLA, PLD, Field Programmable Gate Array(FPGA), Gate Array, or other customized or programmable device. In thecase of a programmable device as well as in other implementations, amemory is required. The memory may include a static RAM, dynamic RAM,flash memory, ROM, or any other data storage medium. The memory mayinclude data, programs, and/or instructions that are executable by theprocessor.

While system 130 in FIG. 13 above was described with regard to twodifferent antennas 52 a and 52 b, respectively serving sub-systems ‘A’and ‘B’, and each used for another non-over-lapping channel, it isapparent that a single antenna 52 may as well be used, serving bothsub-systems. Such configuration is simpler since the cost, mechanicaldesign, and other complexities derived from the presence of two antennasare minimized when a single antenna is used. Using a single antenna isin particular contemplated in the case wherein the two radio frequencybands between which the shifting is made are close to each other, suchas two channels in the 2.4 GHz band employed in IEEE802.11g. Using asingle antenna is exampled as system 130 a in FIG. 13 a, wherein antenna52 a (as well as the RF Filter 51 a) are shared by both systems, and theantenna 52 a is connected in parallel to both sub-system ‘A’ BPF 131 aand TX/RX switch 49 a and to sub-system ‘B’ BPF 131 b and TX/RX switch49 b.

System 120 has numerous advantages over the prior art and typicalfrequency shifters, examples of which include:

a. WLAN transceivers 46 a and 46 b, as well as other parts of frequencyshifter 120 make use of the same components widely used for standard andcommon WLAN units. As such, such components are readily available in themarket and are low priced due to the large volume of manufactured WLANunits. Furthermore, such components are highly integrated today,allowing for minimum parts count, low space/weight requirements and lowpower consumption, together with high reliability. Furthermore, system90 involves both RF/analog and digital hardware in the data path,requiring specific voltages and converters, not required in thesubstantially RF/analog only path of frequency shifter 120.

b. When compared with system 90 implementation, frequency shifter 120does not include any digital processing, and further does not involveany WLAN or Ethernet MAC handling, or any higher layer support.Frequency shifter 120 is basically a physical layer unit, and as suchthe hardware involved with such processing is obviated. Furthermore,installing such a system is easy since related configuration;monitoring, management and similar processes are obviated. Essentially,the only configuration required is setting the required channels to beshifted.

c. Since there is no MAC digital processing or any other digitalhandling of the signal, there is no associated delays in the signalflow, thus the delay through the system is minimal and is practicallyzero. As such, frequency shifter 120 can be used in latency-sensitiveapplications such as streaming audio or video, as well as interactiveapplications such as gaming. In particular, the frequency shifter 120can be used for carrying VoIP data, known to be latency-sensitive.Furthermore, such systems can be easily serialized as describedhereinafter without affecting the total latency of the network.

d. In many systems the I/Q signals are available as part of the systemas shown for system 40 above. Hence it is simpler and easier to usethese existing signals than generating other.

While the invention has been exampled above with regard to shiftingfrequency between two channels of the WLAN IEEE802.11g standard, it willbe appreciated that such frequency shifting will be applicable to anyfrequency shifting of a wireless signal, from any frequency to any othernon-overlapping frequency, without relating to channel boundaries or anystandards. Furthermore, while the above description related tospread-spectrum signals, being DSSS (Direct Sequence Spread Spectrum) orFHSS (Frequency Hopping Spread Spectrum) any type of signals may besimilarly frequency shifted, including narrow-band. Such frequencyshifting can be unidirectional (i.e. ‘one-way’) as described relating tosystem 110 in FIG. 11, or bi-directional as described relating tofrequency shifter 120 in FIG. 12.

Frequency shifting was described above using ‘I’ and ‘Q’ representationsof a signal. Similarly, any other low frequency or any other single ormultiple types of signals that faithfully represent a signal, and can beused in order to generate the replica of the signal, may be equallyused. Preferably, signals used as part of generating the end signal areused. Such representation may be frequency-dependent relating signals(such as I and Q above) or represent any other than frequencycharacteristics of a signal.

According to one embodiment of the invention, frequency shifting is usedto increase the coverage of a wireless network. An improved coveragewireless network 150 is shown in FIG. 15, where the network contains twoWLAN units 40 d (including an antenna 52 e) and 40 c (including anantenna 52 f). WLAN unit 40 d coverage area is shown as circle 151 c,and the area covered by WLAN unit 40 c is shown as circle 151 a. For anon-limiting example, WLAN unit 40 d may be an IEEE802.11g Access-Point,while WLAN unit 40 c may be a corresponding client device, both set tocommunicate over channel 1. The areas shown as 151 a and 151 e (referredto herein as “communication islands”) are not overlapping, hence thereis not a direct wireless communication between WLAN units 40 d and 40 c.Using frequency shifters can connect the two separated communicationislands 151 a and 151 c. Frequency shifters 120 b (including twoantennas 52 c and 52 d) and 120 a (including antennas 52 a and 52 b) areadded. The sub-systems associated with antenna 52 d of frequency shifter120 b and with antenna 52 a of frequency shifter 120 a are set to achannel distinct from channel 1, such as channel 11. Frequency shifters120 b and 120 a are located such that they communicate with each otherover a wireless communication link 152 b using channel 11, and thefrequency shifters 120 b and 120 a are both within the coverage circle151 b. The sub-system associated with antenna 52 c of the frequencyshifter 120 b is set to channel 1, and being within the area 151 e isoperative to communicate over the wireless communication link 152 c withWLAN unit 40 d. Similarly, the sub-system associated with antenna 52 bof the frequency shifter 120 a is set to channel 1, and being within thearea 151 a is operative to communicate over a wireless communicationlink 152 a with WLAN unit 40 c.

The operation of wireless network 150 involves two states. In one state,WLAN unit 40 d is transmitting over channel 1. The transmitted signal isreceived by antenna 52 c over the communication link 152 c. Frequencyshifter 120 b shifts the signal to channel 11 and transmits the shiftedsignal to antenna 52 a using channel 11 over communication link 152 b.The signal received by antenna 52 d in channel 11 is frequency shiftedby frequency shifter 120 a to channel 1, hence reconstructing theoriginal signal over the originally transmitted channel. The shiftedsignal is transmitted from antenna 52 b over channel 1 via thecommunication link 152 a to WLAN unit 40 c. In the other state, thereciprocal data path is affected, wherein signal transmitted from WLANunit 40 c over channel 1 is shifted to channel 11 by frequency shifter120 a and communicated over link 152 b to frequency shifter 120 b.Frequency shifter 120 b shifts the signal back to channel 1, andcommunicates the signal to WLAN unit 40 d over communication link 152 c.

Since the communication between the two frequency shifters 120 a and 120b over communication link 152 b in the area 151 b uses a frequency band(channel 11) which is distinct from the channel or frequency band usedin areas 151 a and 151 b (channel 1), there is no interference betweenthe two signals. It should also be noted that since there is practicallyno delay in the operation of the frequency shifters 120 a and 120 b, thetotal network 150 performance is not degraded, and for all practicalpurposes and applications, the performance will be as if WLAN units 40 eand 40 d are in the same area and communicate directly with each other.It should be noted that the direction of the signal flow is controlledby the WLAN units 40 c and 40 d in a manner similar to the way that suchmanagement would be executed if these units were in direct wirelesscommunication link with each other. The added frequency shifters willautomatically adapt to the network state, thus allowing seamlessoperation in the wireless network 150, without requiring any additionalmanagement capabilities or any other alterations in the WLAN units 40,allowing the use of standard and available devices.

While the invention has been exampled above with regard to shiftingfrequency between two channels of WLAN IEEE802.11g standard, it will beappreciated that such frequency shifting will be applicable to anyfrequency shifting of a wireless signal, from any frequency to any othernon-overlapping frequency, without relating to any channel boundaries orany standards. The network will function in full as long as thecommunication link 152 b uses a frequency band which does not overlapthe frequency band used by communication links 152 a and 152 c.Furthermore, while the invention has been exampled above with regard tolinks 152 a and 152 c using the same channels, distinct channels ordistinct frequency bands may be equally used. In this case, thefrequency shifters 120 b and 120 a will need to be set to the properfrequency bands. Furthermore, while the invention has been exampledabove with regard to only two frequency shifters 120 a and 120 b, itshould be appreciated that additional frequency shifters may be added,resulting in additional coverage areas.

While network 150 is shown as having a single ‘bridging’ wirelesscommunication link 152 b for coupling the two distinct coverage islands151 a and 151 b, multiple distinct communication links may be employed,for coupling more distant location. A non-limiting example of a networkemploying two distinct ‘bridging’ wireless communication links is shownas network 160 in FIG. 16. WLAN units 40 d and 40 e are shown in distantlocations having no direct communication link. Frequency shifters 120 b,120 a, and 120 c are added in order to allow the seamless communicationbetween the WLAN units 40 c and 40 d, both assumed to be usingchannel 1. Communication link 152 b is operative to wirelessly couplefrequency shifters 120 b and 120 a over channel 6. Similarly,communication link 152 a is operative to wirelessly couple frequencyshifters 120 c and 120 a over channel 11. A signal transmitted by WLANunit 40 d over channel 1 is shifted by frequency shifter 120 b tochannel 6 and carried by link 152 b to frequency shifter 120 a, whereinit is shifted to channel 11 and carried over link 152 a to frequencyshifter 120 c, which in turn shifts the signal back to the originalchannel 1, for communicating with WLAN unit 40 c via link 152 d. Whileexampled with the non-overlapping channels 1, 6 and 11, any othernon-overlapping frequency bands may be equally employed.

While systems 150 and 160 were described as using frequency shifters120, it will be appreciated that shifters such as those used in systems90 and 100 described above may be equally used as a substitute.

Buildings are known to be hostile to radio-frequency, the basis ofwireless applications and devices. Stout construction and buildingmaterials, such as steel, thick or mirrored glass windows, concrete,multiple stairwells, and elevator shafts degrade, dilute, and obstructwireless signals, making uniform coverage a major challenge. Theseobstacles may be handled according to one embodiment of the invention asshown in FIG. 17. The figure shows a network including two buildings 171a and 171 b. In each of the buildings 171 a and 171 b there is awireless network having a respectively limited coverage wireless network151 c and 151 a respectively. WLAN units 40 d and 40 c are located inthe respective buildings 171 a and 171 b, and cannot be interconnecteddue to the limited coverage within the building. Similar to system 150described above, frequency shifters 120 a and 120 b are respectivelyadded in buildings 171 b and 171 a respectively, thus allowingcommunication between the involved WLAN units 40 d and 40 c over awireless link 152 b. While shown as different buildings, the samescenario may apply to neighboring apartments in a Multiple DwellingUnits or different rooms in the same building or apartment.

Systems 150 and 170 have been demonstrated to interconnect isolatedshort-range areas. According to one embodiment of the invention, a WLANcommunication link is used to interconnect two or more isolated (W)PAN(Wireless Personal Area Network) systems. The reach of a PAN istypically a few meters, hence such networks are confined to a limitedspace, such as in-room communication. IEEE 802.15 is the working groupof the IEEE 802, which specializes in Wireless PAN (WPAN) standards.Non-limiting examples of WPAN systems include:

-   -   a. Bluetooth, which according to IEEE 802.15.1 standard, for        example, operates over license-free ISM band at 2.45 GHz. An        ad-hoc network of computing devices using Bluetooth technology        protocols is known as piconet.    -   b. Ultra-Wide-band (UWB), which according to the IEEE 802.15.3        standard, for example, uses a wavelet (some times referred to as        wireless USB).    -   c. ZigBee, which according to IEEE 802.15.4 standard, for        example, offers low data rate and low power consumption.    -   d. IEEE 802.11a, commonly considered as WLAN, but since it works        in 5 GHz spectrum its reach is considerably limited, thus        IEEE802.11a be also considered as WPAN.

Any of the above technologies, as well as proprietary networkingschemes, may be used for communication links 152 a and 152 c in network150, respectively covering areas 151 a and 151 c. Interconnecting thecovered areas may make use of WLAN technologies, used to implementcommunication link 152 b in network 150. Currently widespread WLANtechnologies (e.g. WiFi) are based on IEEE 802.11 and include IEEE802.11b which describes a communication using the 2.4 GHz frequency bandand supporting a communication rate of 11 Mb/s, IEEE 802.11a uses the 5GHz frequency band to carry 54 MB/s and IEEE 802.11g uses the 2.4 GHzband to support 54 Mb/s.

In a similar way, the backbone network used for coupling the PANs may bebased on a MAN (Metropolitan area Network) such as HIPERMAN or WiMAX,and may be based on IEEE 802.16, or any wireless WAN (Wide AreaNetwork). Typically wireless MAN and WAN technologies are used forBroadband Wireless Access (BWA) and are commonly based on either LMDS(Local Multipoint Distribution Service) using microwave signalsoperating between 26 GHz and 29 GHz bands supporting point-to-multipointservice up to 5 miles, or MMDS (Multichannel Multipoint DistributionService) which uses microwave bands from 2 GHz to 3 GHz.

In a similar way, the network 150 or 170 may be used to interconnectWLAN systems using WAN or MAN technologies. In such configuration,networks 151 a and 151 c represent WLAN based systems, interconnected bya link 152 b using WAN, MAN or BWA, which may be based on LMDS or MMDS,offering communication within area 151 b.

Some wireless technologies, in particular microwave signals used in theWAN and MAN arenas, are using frequencies above 2-3 GHz where the radiopath is not reflected or refracted to any great extent. Propagation insuch frequencies requires a Line-of-Sight (LOS), that rely on a line ofsight between the transmitting antenna and the receiving antenna. Usingthe concept of network 150 allows for NLOS (Non-LOS) wireless networksto interconnect over a LOS-based communication link. In the non-limitingexample of system 170 in FIG. 17, the communication link betweenfrequency shifters 120 a and 120 b, using respectively antennas 52 a and52 d, may be above 2-3 GHz, hence requiring LOS between the units.However, communication within the buildings 171 a and 171 b with therespective frequency shifters may be well below the gigahertz spectrum,hence allowing NLOS operation.

Wireless technologies are known to use either licensed frequency bandsor unlicensed frequency band, such as the frequency bands utilized inthe Industrial, scientific and Medical (ISM) frequency spectrum. In theUS, three of the bands within the ISM spectrum are the A band, 902-928MHz: the B band, 2.4-2.484 GHz (referred to as 2.4 GHz); and the C band,5.725-5.875 GHz (referred to as 5 GHz). Overlapping and/or similar bandsare used in different regions such as Europe and Japan. According to oneembodiment of the invention, frequency shifting is used to bridgebetween wireless networks using licensed and unlicensed bands. In thenon-limiting example of system 170 in FIG. 17, the wireless networks inareas 151 a and 151 b are respectively confined within buildings 171 band 171 a respectively, and as such, may use licensed frequency bands,since there is a low risk of interfering to or being interfered byanother service rightfully using the same licensed spectrum. However,the communication link 152 b in area 151 b is external to the buildingand as such may use (according to the local law) only an unlicensedband. Similarly, in-building networks may use unlicensed bands such asWLAN IEEE802.11g described above, while the wireless signal forcommunicating the internal networks between the buildings may use alicensed spectrum, thus being more robust and less susceptible to othersignals over the same frequency band.

According to one embodiment of the invention, frequency shifting is usedto improve coverage in a building to a communication tower, such ascommunication between a cell phone and base-station. Such aconfiguration is shown as system 180 in FIG. 18. A cell phone 182 isshown in building 171 b, communicating with a base-station overcommunication tower 181 over communication link 152 e. In order toimprove the in-building reception, a frequency shifter 120 a isprovided, preferably located in the building in a location wherein areasonable signal and good communication is available with the tower 181via antenna 52 a. Optimally, the frequency shifter 120 a is located in aplace where there is a clear and non-interfered LOS to the tower 181.The signal from the tower 181, via link 152 e, is shifted to anotherfrequency and re-transmitted to the air via antenna 52 b covering area151 e, linking with the cellular device 182 via link 152 f.

Attenuation.

The coverage of a wireless system is typically limited, among otherfactors, by two aspects: the power level of the transmitted signal andthe receiver sensitivity. The design goal in wireless transmitters is totransmit the maximum available power, in order to allow distantreceivers to receive a decent signal after attenuation through the air.The transmitting power is typically limited by either regulatoryrequirements (such as those imposed by the FCC in the U.S.), maximumpower defined by the relevant standard, such as IEEE802.11g, andpractical implementation limitations, such as available power toconsume, size of the antenna, and the transmitter, limited heatdissipation and so forth. However, high radio power levels derive thefollowing disadvantages:

-   -   a. High transmitting power level interfere with other radio        networks operating in or around the same frequency band, and add        to general environmental radio pollution;    -   b. Radio radiation may create health hazards to human beings and        other animals;    -   c. A security breach may happen since the transmitted radio        signal may be received by eavesdropping;    -   d. Higher transmitting power warrants more expensive, complex        and large components such as power amplifiers; and    -   e. The power consumption may be reduced since less power is        required to be transmitted, and similarly less receiving        circuitry is required. This is especially important in mobile or        battery-operated devices.

In a similar way, the design goal of radio receivers is typically toincrease the sensitivity in order to allow increased coverage. However,such low sensitivity may result in higher degree of interference fromunwanted remote radio transmitters, and may further cause highersusceptibility to a surrounding noise in the radio bands, thus reducingthe overall communication performance.

In systems based on the present invention, the radio signal is ‘brought’to the required location. The frequency shifters described above may belocated near the stations that are required to communicate with eachother. As a non-limiting example, in a building having multiple rooms, afrequency shifter may be installed only in rooms wherein wirelessdevices are present, and the relevant sub-system in each such shifter isrequired to only cover the room and communicate only with WLAN units inthe room. As such, the radio transceiving functionalities in each room(not to include the shifted frequency band used to connect the twoshifters) are not required to have a large covered area, but rather alimited (in room) coverage. Testing of experimental systems has shownthat using 10 dB or more attenuation in the transmitting power (relativeto a nominal power used as a maximum in IEEE802.11g standard and incommon available WAPs), as well as 10 dB degrading the receivingsensitivity, has not effected the performance in a typical room in abuilding or residence. In the non-limiting example of network 150, shownin FIG. 15 described above, the communications link 152 c and thecovered area 151 c coupling WLAN unit 40 d and frequency shifter 120 bmay not require the full range since they may be located adjacent toeach other. Similarly, the communications link 152 a and the coveredarea 151 a coupling WLAN unit 40 c and shifter 120 a may not require thefull range since they may be located adjacent to each other. This mayapply in a similar way to system 170 shown in FIG. 17 described above,wherein the communication within the house (such as link 151 c betweenWLAN unit 40 d and shifter 120 b) may not require a large distance sincethe devices may be located close to each other.

In such scenario, it will be advantageous to reduce the nominal transmitpower level used for communication with the devices located nearby. Sucha shifter 130 b is shown in FIG. 13 b, and is based on shifter 130 shownin FIG. 13. However, an RF attenuator 251 a is inserted between the RFfilter 51 a and the TX/RX switch 49 a. The attenuator 251 a attenuatesthe transmitted signal sent to the antenna 52 a, thus reducing theenergy transmitted to the air from that antenna 52 a. Similarly, asignal received from the air by antenna 52 a will be attenuated henceeffectively reducing the receiver sensitivity. It is apparent that suchattenuator 251 a may be installed any way along the RF radio signalpath, such as between the RF filter 51 a and the antenna 52 a. Otherways of attenuation such as mismatching and mechanically effecting theantenna construction may as well be used.

In another embodiment according to the present invention shown as system130 c in FIG. 13 c, two attenuators 251 a and 251 b are used. Attenuator251 a, connected between the TX/RX switch 49 a and port 61 a of the WLANtransceiver 46 a, affects the receiving path, and thus impacts thereceiver sensitivity, without any effect on the transmitted signal. Itis apparent that such attenuator may be located anywhere along thereceiving path. Similarly, attenuator 251 b connected between the TX/RXswitch 49 a and port 62 a of the WLAN transceiver 46 a, affects thetransmitting path, and thus impacts the transmitted signal, without anyeffect on the receiver sensitivity. It is apparent that such attenuatormay be located anywhere along the transmitting path. Such configurationallows for selecting different attenuation levels for each path, and nota single value to both paths as shown in system 130 b. In somescenarios, it may be contemplated to use attenuation only in one path,such as in the receiving path only. In this case only attenuator 251 awill be used, and attenuator 251 b will be removed. Similarly, in thecase of attenuating only the transmitting energy, only attenuator 251 bwill be used. While the attenuation function was described above asusing an attenuator 251, it is apparent that the attenuationfunctionality may be executed without using an actual attenuator 251,but rather by controlling gain of an amplifier or other methods known inthe art.

In some cases it may be beneficial to select between a few levels ofattenuation, or even to avoid any attenuation altogether. This may beimplemented by bypassing the RF switch 251 by a parallel connected RFswitch 208, as shown in FIG. 13 b for system 130 b. Upon closing the RFswitch 208 contacts, the attenuator 251 a is bypassed and no attenuationis inserted, retaining the former maximum transmitting power level andsensitivity. Such a switch 208 is controlled by port 203, which may beoperated locally or remotely, or mechanically operated by theinstaller/user/operator. In the latter case, RF switch 208 is amechanical switch. Similar bypassing switches may be connected acrossattenuators 251 a and 251 b in system 130 c.

Plug-In Device.

One approach to adding functionality to existing outlets is by using aplug-in module. Such plug-in modules are described in US PatentApplication Publication US 2002/0039388 to Smart et al. entitled ‘Highdata-rate powerline network system and method’, US Patent ApplicationPublication US 2002/0060617 to Walbeck et al. entitled ‘Modular powerline network adapter’, and also in US Patent Application Publication US2003/0062990 to Schaeffer, J R et al. entitled ‘Powerline bridgeapparatus’. Modules using HomePlug™ technology are available frommultiple sources such as part of PlugLink™ products by Asoka USACorporation of San Carlos, Calif., USA. HomePlug is a trademark ofHomePlug Powerline Alliance, Inc. of San Ramon, Calif., USA. Varioustypes of snap-on devices are also described in US Patent application2005/0180561.

Any of the frequency shifters described above, such as systems 20, 30,90, 110, 120, and 130 and their derivatives may be housed as an outletplug-in enclosure. In one embodiment according to the invention, aplug-in into an AC power outlet is used as such enclosure. A mechanicaloutline of such a plug-in unit 190 is generally shown in FIG. 19 a, witha perspective rear view in FIG. 19 b and front view in FIG. 19 c. ANorth-American style AC power outlet 191 is shown, having two powersockets 192 a and 192 b. The frequency shifter 130, for example,enclosed as plug-in module 190 is shown to have two power prongs 193 aand 193 b respectively mating with sockets 192 a and 192 b, providingelectrical connection as well as mechanical support, enabling theplug-in unit 190 to be easily attached to the outlet 191. Antennas 52 aand 52 b are shown, as well as two corresponding channel selectingmechanical rotary switches 139 a and 139 b, each having 11 positions forselecting one out of the 11 channels of the IEEE802.11g. In the exampleshown, rotary switch 139 a controlling the ‘B’ sub-system channel is setto channel 6, while rotary switch 139 b controlling the ‘A’ sub-systemchannel is set to channel 11. The power connection via prongs 193 a and193 b is used to supply AC power to the unit 190 for powering itsinternal circuits, preferably via a power supply including an AC/DCconverter, for converting the 110 VAC 60 Hz power from the outlet 191 tothe DC voltage or voltages required for proper operation of thefrequency shifter 190.

While the frequency shifter 190 was described as a plug-in module to anAC power outlet, it is apparent that a frequency shifter may be equallyplugged-in to any outlet, being an AC power, telephone, CATV or LAN(such as Structured Wiring based on Category 5, 6 or 7 wiring) outlet.While the shifter 190 was described as being both powered from andmechanically supported by the attached AC power outlet, such couplingmay be only for power feeding or only for mechanical support.

A mechanical outline of a plug-in unit 190 for attaching to a LAN outletis generally shown in FIG. 19 d, with a perspective rear view in FIG. 19e. A typical LAN outlet 196 is shown, comprising a LAN connector 197,such as an RJ-45 jack. The frequency shifter 130, for example, enclosedas plug-in module 195 is shown to have a RJ-45 plug 198 respectivelymating with LAN connector 197, providing electrical connection as wellas mechanical support, enabling the plug-in unit 195 to be easilyattached to the outlet 196. Antennas 52 a and 52 b are shown, as well astwo corresponding channel selecting mechanical rotary switches 139 a and139 b, each having 11 position for selecting one out of the 11 channelsof the IEEE802.11g. In the example shown, rotary switch 139 bcontrolling the ‘B’ sub-system channel is set to channel 6, while rotaryswitch 139 b controlling the ‘A’ sub-system channel is set to channel11. In one embodiment according to the invention, the LAN wiringconnected to the outlet 196 via jack 197 carries a power signal, forexample according to PoE (Power over Ethernet) IEEE802.3af standard,explained below. The plug-in module 195 serves as a PD (Powered Device)and is powered from the LAN wiring, typically via DC/DC converter, asdescribed below.

Outlets

The term “outlet” herein denotes an electro-mechanical device, whichfacilitates easy, rapid connection and disconnection of external devicesto and from wiring installed within a building. An outlet commonly has afixed connection to the wiring, and permits the easy connection ofexternal devices as desired, commonly by means of an integrated standardconnector in a faceplate. The outlet is normally mechanically attachedto, or mounted in, a wall or similar surface. Non-limiting examples ofcommon outlets include: telephone outlets for connecting telephones andrelated devices; CATV outlets for connecting television sets, VCR's, andthe like; outlets used as part of LAN wiring (i.e. “structured wiring”)and electrical outlets for connecting power to electrical appliances.The term “wall” herein denotes any interior or exterior surface of abuilding, including, but not limited to, ceilings and floors, inaddition to vertical walls.

Functional Outlet Approach.

This approach involves substituting the existing service outlets with‘network’ active outlets. Outlets in general (to include LAN structuredwiring, electrical power outlets, telephone outlets, and cabletelevision outlets) have evolved as passive devices being part of thewiring system house infrastructure and solely serving the purpose ofproviding access to the in-wall wiring. However, there is a trendtowards embedding active circuitry in the outlet in order to use them aspart of the home/office network, and typically to provide a standarddata communication interface. In most cases, the circuits added servethe purpose of adding data interface connectivity to the outlet, addedto its basic passive connectivity function.

An outlet supporting both telephony and data interfaces for use withtelephone wiring is disclosed in U.S. Pat. No. 6,549,616, entitled‘Telephone outlet for implementing a local area network over telephonelines and a local area network using such outlets’ to Binder. Anothertelephone outlet is described in U.S. Pat. No. 6,216,160 to Dichter,entitled ‘Automatically configurable computer network’. An example ofhome networking over CATV coaxial cables using outlets is described inWO 02/065229 published 22 Aug. 2002 entitled: ‘Cableran Networking overCoaxial Cables’ to Cohen et al. Such outlets are available as part ofHomeRAN™ system from TMT Ltd. of Jerusalem, Israel. Outlets for use inconjunction with wiring carrying telephony, data and entertainmentsignals are disclosed in US Patent Application PublicationUS2003/0099228 to Alcock entitled ‘Local area and multimedia networkusing radio frequency and coaxial cable’. Outlets for use with combineddata and power using powerlines are described in US Patent ApplicationPublication US2003/0062990 to Schaeffer et al. entitled ‘Powerlinebridge apparatus’. Such power outlets are available as part of PlugLAN™by Asoka USA Corporation of San Carlos, Calif. USA.

While the active outlets have been described above with regard tonetworks formed over wiring used for basic services (e.g. telephone,CATV, and power), it will be appreciated that the invention can beequally applied to outlets used in networks using dedicated wiring. Insuch a case, the outlet circuitry is used to provide additionalinterfaces to an outlet, beyond the basic service of single dataconnectivity interface. For example, it may be used to provide multipledata interfaces, where the wiring supports a single such dataconnection. An example of such an outlet is the Network Jack™ productfamily manufactured by 3Com™ of Santa-Clara, Calif., U.S.A. In addition,such outlets are described in U.S. Pat. No. 6,108,331 to Thompsonentitled ‘Single Medium Wiring Scheme for Multiple Signal Distributionin Building and Access Port Therefor’, as well as U.S. PatentApplication US 2003/0112965 Published Jun. 19, 2003 to McNamara et al.entitled ‘Active Wall Outlet’.

While the active outlets have been described with regard to outlets andnetworks based on conductive media such as wires and cables, it will beappreciated that such outlets are equally applicable in the case whereinthe network medium is non-conductive, such as fiber-optical cabling.Active outlets supporting data interfaces and based on fiber opticcabling are described in U.S. Patent Application US 2002/0146207Published Oct. 10, 2002 to Chu, entitled ‘Fiber Converter FaceplateOutlet’, as well as in U.S. Pat. No. 6,108,331 to Thompson entitled‘Single Medium Wiring Scheme for Multiple Signal Distribution inBuilding and Access Port Therefor’. As such, the term ‘wiring’ as usedin this application, as well as in the appended claims, but not limitedto, should be interpreted to include networks based on non-conductivemedium such as fiber-optics cabling.

While the outlets described above use active circuitry for splitting thedata and service signals, passive implementations are also available. Anexample of such a passive outlet is disclosed in PCT Publication WO02/25920 to Binder entitled ‘Telephone communication system and methodover local area network wiring’. Such outlets are available as part ofthe etherSPLIT™ system from QLynk Communication Inc. of College Station,Tex. USA. The above-described outlets are complete and self-containeddevices. As such, they can be easily installed in new houses instead ofregular passive simple outlets.

In one embodiment according the invention, the frequency shifter ishoused, at least or in part, in an outlet, being an AC power, telephone,CATV or LAN outlet.

Wireless/Wired.

Carrying wireless signal over a cable is known in the art, as describedin U.S. Patent publication '9245. A typical prior-art system is shown inFIG. 20. Typically, in such a system 200, the wireless signal is carriedbetween two wireless units 202 a and 202 b over a coaxial cable 201 as apoint-to-point scheme, wherein the wireless units 202 a and 202 b areeach connected a different end of the cable 201. Coaxial cables areknown to be expensive and difficult to install, maintain, and repair, inparticular when compared to a twisted-pair wiring. US Patent ApplicationPublication 2005/0249245 to Hazani et al. entitled: ‘System and Methodfor Carrying a Wireless based Signal over Wiring’; teaches carryingwireless signals over a medium other than coaxial cable, such as atelephone wire-pair. However, Hazani, et al. describes frequencyshifting using a super-heterodyne based implementation.

According to one embodiment of the invention, frequency-shifted wirelesssignals are carried over a metallic medium such as wiring. An examplewherein a IEEE802.11g signal is carried over a twisted wire pair will bedescribed hereinafter. In this non-limiting example, channel 6 isshifted to the 8÷30 MHz frequency band and carried over a single twistedwire pair.

A frequency shifter for bridging between wireless (IEEE802.11g channel6) and wired (using 8-30 MHz band) mediums is shown as system 210 inFIG. 21. The sub-system ‘A’ of system 210, including antenna 52 a, RFfilter 51 a, WLAN transceiver 46 a, as well as the corresponding part ofcontrol unit 111 are identical or similar to the correspondingsub-system of systems 120 and 130 described above respectively withregard to FIGS. 12 and 13. The sub-system ‘A’ is set to channel 6 byswitch 139 a coupled to the control unit 111, used by the control unit111 for setting via port 79 a, thus converting between channel 6 and itsI/Q component signals. However, the ‘B’ sub-system is modified to workaround 19 MHz center frequency, thus allocating the frequency-shifted 22MHz bandwidth signal between 8 MHz and 30 MHz.

The sub-system ‘B’ of system 210 is in principle similar to thesub-system ‘B’ described above, for example, in FIG. 13 a, howeveradapted for the wired medium interface. Connector 214 is used to coupleto a wire pair. The connector 214 may be RJ-11, for example. Thereceived signal from the wire pair via the connector 214 is passedthrough a protection block 215, for handing surges, over-voltage,lightning, and ensuring a safe and undamaged operation on the system210, and for meeting the required safety and ESD/EMC requirementsimposed by the UL/FCC in the U.S.A. and CE/CENTELEC in Europe. Theprotection block 215 may be based on, for example, P3100SC ‘275VSIDACTOR® Device’ from Littelfuse of Des Plaines, Ill., U.S.A. Band PassFilter (BPF) 216 is provided for passing only the frequency bandrequired (in our example 8-30 MHz) and filtering out any noises orsignal outside this frequency band. As a non-limiting example, a passivefilter based on serially connected four capacitors of 150 pF each and a1.8 μHy inductor connected in parallel, have been used, functioning as aHigh Pass Filter (HPF) and thus rejecting all low frequencies. Anisolation block 218, typically based on a transformer 217, is providedin order to reject common-mode signals and to adapt between the balancedsignal carried over the wire pair to the non-balanced internal circuitryin the system 210. Similar to the TX/RX switch 49 described above, aTX/RX switch 208 is used, adapted to switch the 8÷30 MHz signal betweenreceive and transmit states. In the ‘receive from wire pair’ state, thereceived signal is routed between ports 1 and 2, to an equalizer 206.The equalizer 206 is used to compensate the frequency dependentcharacteristics of the wire pair medium, such as frequency tilt. Theresulting signal is fed to a buffer/amplifier 219 having an AGCfunctionality, in order to adjust to the proper signal level required byI/Q modulator 212 connected via port 61 b. Such AGC amplifier 219 may bebased on RF2637 ‘Receive AGC Amplifier’ from RF Micro Devices, inc. ofGreensboro, N.C. U.S.A. The Q and I component signals are outputted viarespective ports 65 ab and 65 bb to the WLAN transceiver 46 a, to befrequency shifted to channel 6 and transmitted via antenna 52 a asdescribed above.

The signal path from the antenna 52 a to the wire pair 201 via connector214 is reciprocal to the above. The signal received in channel 6 isdemodulated to its Q and I component signals, respectively fed to theI/Q modulator 213 via the respective ports 66 ab and 66 bb. The combinedsignal at the target frequency band 8÷30 MHz is connected to a linedriver 207 via port 62 b. The line driver 207 is adapted to drive thesignal to the wired median, and may be based on EL5130 ‘500 MHz LowNoise Amplifier’ from Intersil Corporation headquartered in Milpita,Calif., U.S.A. TX/RX switch 208 in the ‘transmit to wire pair’ stateroutes the signal through ports 3 and 1 to the isolation unit 218. Sucha switch may be based on TS5V330 ‘Quad SPDT Wide-Bandwidth Video Switchwith Low On-State Resistance’ from Texas Instruments Incorporated ofDallas Tex., U.S.A. The balanced signal is filtered by the BPF 216, andfed through the protection block 215 to the wire pair 201 via connector214. The center frequency of the sub-system ‘B’ is sent from the controlunit 111 to the reference frequency source 25 b and the related crystal64 b, via port 79 b.

I/Q Demodulator 212 and I/Q modulator 213 may be implemented asseparated circuits, or can be integrated into a single component 211,which may be based on Maxim MAX2450 3V, Ultra-Low-Power QuadratureModulator/Demodulator from Maxim Integrated Products of Sunnyvale,Calif. U.S.A. In some cases, WLAN transceivers such as 46 may also beused, if the required wired frequency band is supported. Similar to thediscussion above involving systems 120 and 130, wherein system 210 isnot idling, it may be in two states. In the first state the signal isreceived from the air via antenna 52 a and fed after frequencydownshifting to the wire pair via connector 214. In the second state thesignal is received from the wire pair 201 via connector 214 andtransmitted after frequency up-shifting to the air via antenna 52 a. Thetwo states are determined by control unit 111 in a way similar to thedescription above, subject to the required changes of controlling TX/RXSwitch 208 via connection 203, and determining the signal availabilityover the wire pair by detector (DET) 205, connected to the control unit111 via connection 204. Such a detector 205 may be based on LTC5507 ‘100kHz to 1 GHz RF Power Detector’ from Linear Technology Corporation ofMilpitas, Calif., U.S.A.

While system 210 has been described as supporting two-way operation, itwould be apparent that a one-way operation may be implemented as well.The unidirectional operation may involve either from the air to thewire-pair or from the wire-pair 201 to the air. In each such anembodiment, the functions and parts not used in the operation may beobviated.

While the invention has been exampled above with regard to a channel ofWLAN IEEE802.11g standard, it will be appreciated that such frequencyshifting will be applicable to any frequency shifting of any wirelesssignal, from any frequency to any other frequency, without relating tochannel boundaries or any standards. Similarly, while the system wasdescribed above involved carrying the signal over the wire pair 201 inthe 8-30 MHz frequency spectrum, it will be appreciated that thefrequency band may be equally used.

Using frequency shifting for increasing the coverage of a wirelessnetwork based on a wired medium as the backbone is shown as system 220in FIG. 22. As part of the system 220 a WLAN unit 40 b (includingantenna 52 d) is located in a remote location (or hidden for wirelesscommunication purposes) from WLAN unit 40 a (including antenna 52 c),and as such there is no communication link between the WLAN units. Atwisted pair 201 is provided, having end-points that are in proximity tothe WLAN units. A frequency shifter 210 a having antenna 52 a isconnected to one end of the wire pair 201, and another frequency shifter210 b (including antenna 52 b) is connected to the other end of thetwisted wire pair 201. A radio signal transmitted by WLAN unit 40 b viaantenna 52 d is received in antenna 52 a of the shifter 210 a, allowingfor a wireless communication link 152 b between the two wirelesslycoupled devices. The received signal is down frequency shifted andtransmitted to the wire pair 201. The signal propagates through the wirepair 201 and is received at the other end by shifter 210 b, whichup-shifts and reconstructs the original signal, which is transmittedover the air from antenna 52 b to antenna 52 c over wirelesscommunication link 152 a. The opposite direction is reciprocal, whereinthe wireless signal from antenna 52 c is regenerated over link 152 bafter being conveyed over the twisted wire pair 201.

Since the latency through the shifters 210 a and 210 b and the wire pair201 is small and can be practically ignored, WLAN unit 40 b and 40 a areconsidered for all practical purposes to be wirelessly in directcommunication. The system 220 may be in one out of states, each state isdefined by the direction of the signal flow, are controlled by the WLANunits 40 in the same manner as if the WLAN units 40 were in directwireless communication, and the added backbone (including the wire pair201, and shifters 210 a and 210 b) is automatically adapting to supportthe required configuration. As such, no alterations or modifications arerequired to the WLAN units 40, allowing for the use of standard andavailable devices.

Twisted wire pair 201 may be a UTP (unshielded Twisted Pair), FTP(Foiled Twisted Pair), S/STP (Screened Shielded Twisted Pair) or an STP(Shielded Twisted Pair), as well as any other type used in wired LANcabling, such as “structured wiring”. Furthermore, such cabling mayconform to EIA/TIA-568, such as category 1, 2, 3, 4, 5 or 6. Inaddition, the two conductors of the wire pair 201 may be conductingpaths over a Printed Circuit Board (PCB). Similarly, coaxial cable maybe used, such as RG-59/U. In addition, any two conductors or any twowires, even if they were not specifically manufactured for carrying dataor any communication, such as power cables, may be used. Wirelessnetworks, in general, typically support large dynamic range in order tocompensate for the fading, loss, and attenuation through the air. Inaddition, spread-spectrum is used in order to accommodate interferencesand other impairment associated with the radio-based over the aircommunication medium. For example, IEEE802.11g uses OFDM modulation andtypically supports above the 90 dB dynamic range. As such, carrying awireless signal over a wired medium allows for high attenuation anddistortion, allowing carrying the signal over a wired medium having poortransmission capability, while still offering large reach added torobust and reliable operation. Yet, these advantages are obtainedwithout using any dedicated modem or any special processing. Forexample, an experimental system 220 was built and (without any equalizer206) had over 1500 foot reach over a relatively low-grade category 3twisted wire pair 201. The connection to each side of the wire pair 201commonly employs a connector, preferably a standard based connector.

Wireless systems are typically built to accommodate the effect ofmulti-path, causing constructive and destructive interference as well asphase shifting of the signal. Powerful algorithms and complex line codemodulations such as spread-spectrum are commonly used in order toprovide a reliable communication even in a severe multi-pathenvironment.

While system 220 in FIG. 22 was shown to include only two shifters 210 aand 210 b connected in a point-to-point topology to the two ends of thetwisted wire pair 201, any number of shifters 210 interconnected via thewired medium in any topology may be used. One non-limiting example issystem 230 shown in FIG. 23. System 230 uses a single wire pair 201,interconnecting shifters 210 a, 210 b and 210 c, respectively includingantennas 52 a, 52 b and 52 c. While shifter 210 a is connected to oneend of the cable or wire pair 201, shifters 210 b and 210 c areconnected to distinct points along the wire pair 201, leaving the otherend of the wire pair 201 open. Other ‘bus’ topologies, including ‘star’,‘tree’, and any other shared medium or point-to-multipoint topologiesmay be equally used. In any wired network other than point-to-pointhaving properly defined and terminated end-points, a reflection occursin all points wherein the characteristic impedance is not continuousalong the signal propagation. Hence, a reflection signal will begenerated at least in the non-terminated/non-connected end of the wirepair 201. In the case wherein shifter 210 a is not terminated, itsconnection point will cause reflections as well. Such reflections arebasically electrically equal in their characteristics to the multi-pathphenomenon described above. Since system 230 uses wireless signal andwireless end units (such as 40 b and 40 a in system 220) which are builtto accommodate such impairments, system performance will not besubstantially degraded relative to the reflection-free system 220.Hence, there is no need to add any hardware or functionality to theshifters 210 to specifically adapt to any specific topology.

Wireless communication is considered a shared medium environment.Similarly, in system 230 the wire pair 201 served as a sharedcommunication medium to the connected shifters 210. In both cases achannel access method mechanism is used in order to enable only a singletransmitter at a time to transmit to the shared physical communicationmedium and to handle collisions. In an IEEE802.11g (i.e., WiFi) network,a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)scheme is employed. Since the shifters based wired backbone, includingshifters 210 a, 210 b and 210 c and the interconnecting wire pair 201are practically ‘transparent’ to the coupled WLAN units 40 (due to thelow latency and to the fact that the signals are faithfully replicated),there is no need to modify the shifters 210 in any way to support theCSMA/CA or any other channel access method. The wireless networkaffected by the WLAN units and the wired backbone functions as if allthe WLAN units are within a direct communication link with each other.

While the invention has been so far exampled by a wire pair 201 carryingonly the frequency-shifted wireless signal, other signals can beconcurrently carried over the same wire pair 201. For example, TDM (TimeDivision/Domain Multiplexing) may be used, wherein another signal usesthe wire pair 201 in the idle period wherein no signal is propagatedthrough the wired medium. In such a case, the other signal may use thesame or partly the same frequency spectrum used by the frequency-shiftedwireless signal. Alternatively, FDM (Frequency Division/DomainMultiplexing) may be used, wherein the other signal uses a frequencyband distinct from the one used by the frequency-shifted wirelesssignal.

As described above, frequency shifting in general and in particularaccording to the invention, allows for increasing a wireless networkcoverage and allows for connecting wirelessly-separated areas, and thisis provided with the advantages of minimum parts count, highreliability, higher degree of integration, and low power consumption.Furthermore, in many cases the wireless coverage is required in anoutdoor environment or another location requiring hardenedimplementation, such as operating over a wide temperature range, in avibrating or shock-susceptible mechanical stress and so forth.Similarly, such a remote location may be limited in space and lacking anearby power source. The low power consumption of the shifter 210 allowsfor remote feeding of a frequency shifter 210 over the same wire-pair.Such a system 240 is shown in FIG. 24, using FDM to carry DC power(effectively 0 Hz) and frequency-shifted wireless signals in a higherfrequency band (e.g. 8-30 MHz). While remote power feeding is known inthe art, high voltage is typically used in order to compensate for thewiring resistance caused voltage drop. For example, a 120 VDC is used toremotely power feed some of the DSL equipment. Using such voltage levelmay be problematic since many safety standards such as UL/IEC 60950 andEN60950 limit the voltage level in many applications to 60 VDC. The lowpower consumption of a frequency shifter allows for using such lowerthan 60 VDC voltage level, and as such the common 48 VDC voltage levelmay be used and yet support long wiring as well as low diameter/highresistance types of wires.

System 240 is based on system 220 shown in FIG. 22, wherein WLAN 40 band 40 a communicate via the wired backbone including wire pair 201 andinterconnecting shifters 210 a and 210 b. Two HPFs (High Pass Filter)221 a and 221 b are connected respectively between shifters 210 a and210 b and the corresponding end of the wire pair 201. The HPFs 221 allowpassing of the shifted wireless signal band (8-30 MHz in the aboveexample) and block the DC signal available over the wire pair 201, andas such, operation of system 220 is fully restored and is not affected.HPF 221 may be built by simple serially connected capacitors 228 aa and228 ba, since the signal lower frequency component (8 MHz) issubstantially above the DC signal. In some cases, BPF may be used forpassing only the frequency shifter wireless signal. Similarly, HPF 221 bcomprises serially connected capacitors 228 ab and 228 bb. Other typesof filters may be used, such as filter 216 described above. In somecases, the filter 221 may substitute the filter 216 in the shifter 210,and filter 216 may thus be obviated. LPFs 222 a and 222 b are connectedto the end of the wire pair 201 respectively in parallel to theconnection of HPFs 221 a and 221 b. The filters 222 are operative topass only DC, and may comprise two serially connected inductors, such asinductors 223 aa and 223 ba in LPF 222 a, and inductors 223 ab and 223bb in LPF 222 b. Power supply 224 is typically fed from the AC powermains (115 VAC/60 Hz in the US and 220 VAC/50 Hz in Europe) and commonlyincludes an AC/DC converter. The DC power signal is passed through LPF222 a and is fed to the wire pair 201. A system 242 is located at andconnected to the other end of the wire pair 201, and includes a DC/DCconverter 225. A LPF 222 b, a load 227, an HPF 221 b and frequencyshifter 210 b. The DC/DC converter 225 is connected to receive the DCpower signal from the wire pair 201 through the LPF 222 b, and providesa DC power output for powering any load. A general load 227 may beconnected to the DC/DC converter 225 outputs to be fed therefrom. In oneembodiment, the DC/DC converter 225 DC output power is connected to feedthe frequency shifter 210 b via connections 226 a and 226 b, thusrelieving this side of the wire pair 201 to be connected to any localpower source. In another embodiment, the DC/DC 225 feeds both a load 227and the frequency shifter 210 b.

While system 240 is shown in FIG. 24 to have a single fed location atthe other end of the wire pair 201 including the load 227 or shifter 210b, or both, it should be apparent that multiple such remote locationsmay be connected along the cable 201, such as shown in FIG. 23, and notlimited to a point-to-point topology. Each such connected location needsto have an LPF 222 b and a power converter such as DC/DC Converter 225,operative for converting the input voltage from the wire pair 201 to theapplication operational voltage or voltages. Furthermore, a combinationof wire-powered and local-powered locations may be employed. Somepowered locations may be having only a shifter 210 powered, or havingother loads 227 powered, or wherein both the shifter 210 and a load 227are remotely powered. A non-limiting example of a ‘star’ or‘point-to-multipoint’ topology network is shown in FIG. 24 a showing asystem 245. The system 245 shows three remote locations 242 a, 242 b and242 c, respectively including antennas 52 a, 52 b and 52 c, andrespectively connected via wire pairs 201 a, 201 b and 201 c to thecenter location HPF 221 a and LPF 222 a. All or part of the remotelocations 242 may be remotely powered, and one or more such remotelocations 242 may include a remotely powered load 227. Furthermore, eachof the wire pairs 201 may contain different types of wire pairs, forexample wire pair 201 a may be a UTP, wire pair 201 b may be a coaxialcable, and wire pair 201 c may be an STP.

While system 240 was described with a DC power feeding, an AC powerfeeding may also be employed. In such a case, the power supply 224 willgenerate an AC signal and will include an AC/AC converter, and the DC/DCconverter 225 will be substituted with AC/DC converter. In the case theAC power is using a low frequency band signal, the LPFs 222 a and 222 bwill be adapted to pass this low frequency. In the case higher frequencyis used, the LPFs 222 a and 222 b will be substituted with BPFs adaptedto substantially pass the frequency of the AC power signal carried overthe wire pair 201.

Various types of antennas 52 (or any other radio ports) are used in WLANunits. Among those are PCB printed antennas, chip antennas, as well aspanel and dome antennas. Furthermore, the antennas may beomni-directional or directional. Typically, the antennas are coupled tothe WLAN unit enclosure using mating coaxial connectors, such as SMA,N-Type and IPX, providing both the electrical connection as well as themechanical attachment. In many cases, the antenna connection allows foreasy disconnection and connection by means of snapping or screwing. Thecouplings of the antennas 52 d and 52 c to the respective WLAN units 40b and 40 a are designated as ports 241 b and 241 a respectively, asshown in system 240 (FIG. 24) and system 245 (FIG. 24 a). Any type ofantenna may be used for shifter 210, and similarly any antenna coupling(either electrical or mechanical or both) may be used. In particular,any type of antenna that is suitable for WLAN units 40, hence suitableto work in the appropriate frequency range, is equally suitable to beused for shifter 210 communicating over the same frequency band. Forexample, any antenna for IEEE802.11g WLAN unit is operative in the 2.4GHz band and as such may be used in a shifter 210 wirelesslycommunicating with such WLAN unit. The couplings of the antennas 52 aand 52 b to the respective shifters 210 a and 210 b are designated asports 241 c and 241 d respectively, as shown in system 240 (FIG. 24) andsystem 245 (FIG. 24 a).

The invention has been so far described with regard to wirelesscommunication link 152 between the shifters (either 120 or 210) and theWLAN unit 40. However, a direct conductive connection may also be used.In one non-limiting example, there is a direct connection between theantenna ports of the WLAN unit and the shifter. Such a system 250 isshown in FIG. 25. In general, system 250 is based on system 240, shownin FIG. 24. However, in contrast to system 240 where the WLAN unit 40 bwas wirelessly coupled to the shifter 210 a via the respective antennas52 d and 52 a over wireless link 152 b, in system 250 there is ametallic (or any other conductive) connection between the units.Antennas 52 d and 52 a are removed (or bypassed), and there is a wiredconnection between port 241 b of WLAN unit 40 b to port 241 c of shifter210 a, therefore there is no radio radiation in the location of WLANunit 40 b, since WLAN unit 40 b and shifter 210 a are both without anyantenna. Since typically a wireless receiver is design to receivesignals after being attenuated via the propagation through the air, adirect connection may either damage or saturate the receiving unit. Inorder to avoid such phenomenon, an attenuator 251 is connected betweenboth antenna ports 241 b and 241 c. The attenuator 251 should beimpedance matched to both ports since it mimics antenna to the connectedunit, and should at least attenuate the transmitted signal to meet themaximum properly operable received signal. On the other hand, theattenuator 251 should not attenuate the signal such that thecommunication between the connected units will be degraded. In general,any attenuator working in the required frequency band and properlymatched may be used. Attenuation values of 10 dB at least and 80 dBmaximum are recommended. Active as well as passive based scheme of anattenuator scheme may be used. A simple ‘PI’ or ‘T’ topology, single ormulti stages resistor-based may as well be used, offering low cost andminimum space requirements. A simple one stage ‘T’ type attenuator isshown in FIG. 25, containing of two resistors 253 a and 253 b connectedin series, and one resistor 253 c connected in parallel. In anexperimental 50Ω impedance matching system, a value of 40 dB wasimplemented by using a nominal value of 49Ω for resistors 253 a and 253b, and a value of 1Ω for resistor 253 c.

The metallic connection between units 40 b and 210 a, and since they aretypically adjacently located, may contemplate to house both WLAN unit 40b and shifter 210 a, as well as the connecting cable and the attenuator251 in a single enclosure 252, as shown in FIG. 25.

Such a system 250 can be employed in many cases wherein the WLAN unit 40b (such as a WAP—Wireless Access Point) is located in one place, whilethe wireless coverage is required elsewhere, in a remote location. Inone non-limiting example, a power supply may be available only in a oneplace, while the coverage required at the other places not in the samevicinity. In this case, the WLAN unit 40 b will be located at the placewhere the power source (e.g., AC power outlet) is provided, and sinceonly a small part of power is required in the remote location, it willbe carried over the wire pair, with the shifted wireless signal, to theremote location, where the actual wireless coverage is required. Forexample, a WAP may be located in a basement of a building and connectedto be powered from a nearby AC power outlet, and the wire pair willallow the actual wireless communication in a preferred location such asin a ceiling in another part of the building, wherein the antennalocation is optimized by means of providing wide coverage or a coveragein a specific place. Similarly, space constraints may also imposelocalizing the WAP, having more hardware and thus typically being largerin size than the shifter 210, in a place remote from the location, wherethe actual wireless coverage area is required. Other consideration mayinvolve locating the WLAN unit 40 b in a place accessible for easyconfiguration, installation, and maintenance, while keeping the wirelessantenna practically elsewhere. Furthermore, the WLAN unit 40 b may beintegrated with other devices such as an ADSL modem, for example, whichis required to be connected to a nearby telephone outlet.

Device 252 was shown above as part of system 250 in FIG. 25, andincludes a WLAN unit 40 b, attenuator 251, and shifter 210 a. Duringoperation, data received in port 41 of WLAN unit 40 b is I/Q converted,and then modulated and frequency up-shifted to 2.4 GHz radio signal, asdescribed above regarding FIG. 4, exampled with regard to the IEEE802.11g system. The radio signal is attenuated by attenuator 251 and fedto shifter 210 a, where the radio signal is demodulated to anddown-shifted to an I/Q signal, and then modulated again to a signal tobe carried over the wire pair 201. Since there is no need for radiocommunication near device 252, there is no need to create the 2.4 GHzradio signal, and there can be a direct conversion between the wireddata signal received in port 41 and the signal carried over the wirepair 201. A system 260 carrying such direct conversion is shown in FIG.26.

System 260, shown in FIG. 26, provides at least similar or identicalfunctionality as device 252, yet being less complicated and using lesshardware. The ‘B’ sub-system of system 260 is identical or at leastsimilar to the ‘B’ sub-system described for system 210 in FIG. 21 above,and is used for converting between the signal at connector 214 and itsI/Q component signals at ports 65 and 66 of unit 211. The ‘A’ sub-systemis identical or at least similar to the relevant part of WLAN unit 40shown in FIG. 4 above, and contains I/Q modulator/demodulator 45,transmitter/receiver 44. MAC layer processor 43, Ethernet 10/100BaseTPHY 42, and wired port 41. This ‘A’ sub-system is operative to convertbetween data signals (such as IEEE 802.3 10/100BaseT) at port 41 andtheir I/Q component signals at ports 65 and 66 of I/QModulator/Demodulator 45. Similar to that described above, the two I/Qcomponent signals, representing the data signals at port 41 and thewired signals at port 214 are connected in a ‘back-to-back’configuration, operative to convert signals between the two ports 214and 41 via their I/Q representations. Hence system 260 may be asubstitute to unit 252 shown in FIG. 25.

The direct metallic connection between WLAN unit 40 b and shifter 210 a,shown included in system 252 as part of system 250 in FIG. 25, hasmultiple advantages. First, such configuration allows for separating thephysical location of a wireless unit 40 b, such as WAP, from therequired coverage area by link 152 a. Second, compared to wirelesscoupling such as 152 b in system 240, such wired/conductive connectionallows a controlled signal level in input of the receivers of bothconnected units, as well as connection which is more robust and highlyimmune from wireless interference and external noise. As such, it may becontemplated to use such direct and metallic based coupling even in thecase where a wireless coverage area is required near the WLAN unit 40 b.A system 270 shown in FIG. 27 allows for a conductive connection betweenthe WLAN unit 40 b and shifter 210 a, without eliminating or degradingthe wireless communication functionality of the WLAN unit 40 b. Ingeneral, system 270 is based on system 240, wherein a splitter 271 isadded between the antenna port 241 b and the antenna 52 a of WLAN unit40 b. The splitter 271 allows a signal to pass between the antenna 52 aand the antenna port 241 b of the WLAN unit 40 b, thus substantiallyretaining the full functionality of system 240, allowing WLAN unit 40 cto wirelessly communicate with WLAN unit 40 b over the air usingwireless communication link 152 b. In addition, the third port of thesplitter 271 is connected to shifter 210 a via attenuator 251, thusforming a direct metallic connection similar to the connection shown forsystem 250. In some embodiments internal attenuation of the splitter 271may suffice, hence obviating the need for attenuator 251. In otherembodiments, only the value of attenuation will be amended (typicallyreduced), taking into account the attenuation of attenuator 271 in thispath. Hence, both functionalities of systems 240 and 250 aresubstantially retained.

System 240 in FIG. 24 shows a wireless couplings 152 a and 152 b in bothlocations. System 250 in FIG. 25 shows a wired coupling through theattenuator 251 in one location, and a wireless communication link 152 ain the other location. System 270 in FIG. 27 shows a combined wirelesslink 152 b and wired connection (through attenuator 251) in onelocation, and through the air wireless communication link 152 a in theother location. It should be appreciated that each location isindependent from the other location, and each such location may be anyof the above options, independently from the other location orlocations. A non-limiting example is shown as system 275 in FIG. 27 a,where both locations combine both wired and wireless links. In thepowering location (left side of the figure) the arrangement is similarto the one showed in FIG. 27, wherein WLAN with 40 b is metallicallyconnected to shifter 210 a through splitter 271 a and attenuator 251 a.A wireless communication between WLAN unit 40 b and another WLAN unit 40c is retained through antenna 52 a coupled to the splitter 271 a.Similarly, the powered/remote location combines both wired and wirelesscoupling, wherein WLAN unit 40 a is metallically connected to shifter210 b through splitter 271 b and attenuator 251 b. A wirelesscommunication between WLAN unit 40 a and another WLAN unit 40 d isretained through antenna 52 b coupled to the splitter 271 b. In asimilar way, other options may be implemented independently in allconnected locations, being powering or powered sites, and of course alsoin the case wherein line powering is not implemented at all.

While the embodiments above have been described with regard to a setincluding a LPF 222 and an HPF 221 as means for combining and separatingthe DC (or AC) power signal and the frequency shifted wireless signal,an embodiment based on a split center tap transformer may as well beused, as shown for system 279 in FIG. 27 b. A transformer 278 a andcapacitor 276 a are provided as a substitute to the HPF 221 a and LPF222 a of system 275 and are connected to one end of the wire pair 201.Similarly, a transformer 278 b and capacitor 276 b are provided as asubstitute to the HPF 221 b and LPF 222 b of system 275, and areconnected to the other end of the wire pair 201. Such split center-taptransformer arrangement is known in the art and typically only used fortelephony applications. The transformer 278 a includes a primary winding277 a connected to the shifter 210 a, and the secondary winding is splitinto two separated secondary windings 277 c and 277 b, connected to eachother by a capacitor 276 a, which is connected to the DC power supply224. The secondary windings 277 c and 277 b are connected to the wirepair 201. The capacitor 276 a value is substantially low impedance inthe shifted wireless signal frequency band (e.g. 8-30 MHz as above),hence the shifted wireless signal to and from shifter 210 a istransparently passed to the wire pair 201. The capacitor 276 a exhibitsa high impedance value to the DC signal, thus allowing the DC current toflow to the wire pair 201 through the secondary windings 277 c and 277b.

Similarly in the other end of the wire pair 201, The transformer 278 bincludes a primary winding 277 d connected to the shifter 210 b, and twoseparated secondary windings 277 f and 277 e, connected to each other bya capacitor 276 b, which is connected to the DC/DC converter 225. Thesecondary windings 277 f and 277 e are connected to the wire pair 201.The capacitor 276 b value is substantially low impedance in the shiftedwireless signal frequency band (e.g. 8-30 MHz as above), hence theshifted wireless signal to and from shifter 210 b is transparentlypassed to the wire pair 201. The capacitor 276 b exhibits a highimpedance value to the DC signal, thus allowing the DC current to flowfrom the wire pair 201 through the secondary windings 277 f and 277 e tothe DC/DC converter 225.

Referring now to FIG. 28, showing a system 280, which is based on system275 shown in FIG. 27 a. In this system 280 a Limiter/Sensor 281 is addedbetween the power supply 224 and the LPF 222 a. The Limiter/Sensor 281includes a current limiter and other protection means, for limiting thecurrent in the wire pair 201, for example in the case of a short circuitbetween the two conductors of wire pair 201. The Limiter/sensor 281 mayuse a fuse, either resettable or one-time, or an active circuit ofcurrent limiter known in the art. Such current limiting is required, forexample, to meet safety standards. The Limiter/Sensor 281 may alsoinclude a switch, either mechanical or electronic, which may be, forexample, controlled by a processor or other control means. The switchmay connect or disconnect the power to pair according to a pre-definedlogic or rules. In one embodiment, the Limiter/sensor 281 includes acurrent sensing/metering function, allowing the powering site toidentify that a remote load is connected at the remote location. If sucha load is not present, the switch may disconnect the power in order toavoid unnecessary DC voltage over the wire pair 201.

The remote site 284 is shown as including all the hardware conductivelycoupled to the remote side of the wire pair 201, including the shiftedwireless signal handling functions, such as HPF 221 b, shifter 210 bhaving an antenna port 241 d, attenuator 251 b, splitter 271 b coupledto antenna 52 b, and WLAN unit 40 a coupled to the splitter 271 b viaantenna port 241 a. The remote location 284 similarly comprises allpower handling functions such as LPF 222 b, Diode bridge 282,Signature/isolation block 283, and DC/DC converter 225, and may alsoinclude the DC powered load 227. The powering site/location 285 is shownas including all the hardware conductively coupled to the other side ofthe wire pair 201, including the shifted wireless signal handlingfunctions such as HPF 221 a, shifter 210 a having an antenna port 241 c,attenuator 251 a, splitter 271 a coupled to antenna 52 a, and WLAN unit40 b coupled to the splitter 271 a via antenna port 241 b. The poweringlocation 285 similarly comprises all power handling functions such asLPF 222 a, Limiter/sensor 281, and Power Supply 224, which is AC poweredand fed via AC plug 229.

The Diode Bridge 282 added between the LPF 222 b and the DC/DC converter225 is used in order to accommodate a potential wire swapping that willresult in a reversed DC voltage polarity. The Diode Bridge 282 typicallycomprises four diodes and outputs the proper polarity of the DC voltageeven in the case of a reversed input voltage polarity. TheSignature/Isolation block 283 is added between the Diode Bridge 282 andthe DC/DC converter 225. Such Signature/Isolation block 283 typicallycomprises a specific load for indicating the limiter/sensor 281 of thepresence of a powered device in the remote location. Furthermore, thisfunction may also be used to classify the type of the remote location284, and for example may relate to the power consumption of the remotelocation 284. An isolation function may also be included in theSignature/Isolation block 283 for allowing passing of the power onlyafter power detection and classification, and for ensuring such DC powerfeeding that will not damage the connected units. Such isolationfunction may be implemented by using a FET transistor based switch. Theadded blocks Limiter/Sensor 281. Diode bridge 282, and theSignature/Isolation 283 may conform to the PoE (Power over Ethernet)standard described in more detail below.

System 245 shown above in FIG. 24 a describes a network having multipleremote locations 242 a, 242 b and 242 c, connected to the ‘center’location using respective three wire pairs 201 a, 201 b, and 201 c. Suchconfiguration has the following disadvantages:

-   -   1. Since all the wire pairs 201 a, 201 b and 201 c are connected        to each other, a short circuit in any one of the wire pairs 201        will result a whole system shutdown, for both the communication        of the shifter wireless signal and for the DC power carried over        these wire pairs.    -   2. Such topology is known to be inferior to a ‘point to point’        topology as a communication medium, since proper terminations        cannot be adequately employed, thus creating impedance mismatch        and reflections.    -   3. It is more difficult to locate and isolate a fault in the        system, thus complicating the maintenance of such configuration.

Point-to-point topology is long blown to solve the above disadvantagesand to provide a better medium for both DC power carrying and forconveying the shifted wireless signal. According to one embodimentaccording to the present invention, the system 240 shown in FIG. 24,system 280 shown in FIG. 28 or any other similar system is duplicated ineach remote location, hence creating a full and independent replica foreach remote location or each wire pair 201. Such a system is complex,costly, requires a lot of space, and is highly power consuming. Onealternative solution is shown as system 290 in FIG. 29. In such a system290, only one WLAN unit 40 b, preferably being an access point, is usedand shared by all locations. Such configuration allows for the use of asingle WLAN unit 40 b, thus reducing the total complexity, cost, spaceand power consumption, as well as reducing installation and maintenancerequirements. Similar to the above discussion (for example relating tosystem 270 shown in FIG. 27), a splitter 271 a is added between the WLANunit 40 b antenna port 241 b and the antenna 52 a. This connectionallows for local wireless communication in the vicinity of the WLAN unit40 b. In the case that such wireless coverage is not required in thislocation, antenna 52 a (as well as the respective port of the splitter271 a) may be obviated. In contrast to the three ports splitter 271shown as a part of system 270 of FIG. 27, splitter 271 a provides a portfor each required remote location. System 290 is exampled as includingthree remote locations 284 a, 284 b, and 284 c connected via wire pairs201 a, 201 b and 201 c, respectively, each connected to the relevantsplitter 271 a port via the respective connections 291 a, 291 b and 291c. In order to support three remote locations, as well as antenna 52 aand WLAN unit 40 b port, a total of five ports are required (four portsin the case wherein antenna 52 b is not used). It should apparent thatany number of remote locations 284 may be equally supported, simply byadding ports in the splitter 271 a and by providing the appropriatesystems. Supporting a remote location 284 a is provided by attenuator251 a, which is connected between the connection 291 a and the shifter210 a, and wherein the shifter 210 a connects to the wire pair 201 athrough the HPF 221 a, similarly to that explained above. Similarly, theremote location 284 b is provided by attenuator 251 b, which isconnected between the connection 291 b and the shifter 210 b, andwherein the shifter 210 b connects to the wire pair 201 b through theHPF 221 b. Similarly, the remote location 284 c is provided byattenuator 251 c which is connected between the connection 291 c and theshifter 210 c, and wherein the shifter 210 c connects to the wire pair201 c through the HPF 221 c. While three attenuators 251 a, 251 b and251 c are shown, it is apparent that a single attenuator 251 may beused, connected between the antenna port 241 b of WLAN unit 40 b and thesplitter 271 a, and thus obviating the need to provide attenuator pereach remote location 284. As can be seen from the FIG. 29, all thecommunication links are based on separated wire pairs 201, eachconnected in a point-to-point topology to enable superior communicationcharacteristics such as long distance and robust operation.

In one embodiment according to the present invention, no remote poweringis employed, and each location is locally powered. In an alternativeembodiment, as in system 290 shown in FIG. 29, common functions can beintegrated into a single device or function. A single AC main powerconnection 229 is used, feeding a single power supply 224. However, thepower supply 224 should now be able to remotely feed all remotelypowered locations 284. The DC power signal at the power supply 224 isfeeding the Limiter/sensor 281 a, which connects to the wire pair 201 athrough the LPF 222 a. Similarly, remote location 284 b is fed from theLimiter/sensor 281 b, which connects the wire pair 201 b through the LPF222 b. Remote location 284 c is fed from the Limiter/Sensor 281 c, whichconnects the wire pair 201 c through the LPF 222 c. As can be seen fromFIG. 29, all the power links are based on separated wire pairs 201, eachconnected in a point-to-point topology and controlled independently,such that a short circuit in one of the wire pairs 201 will effect onlythe communication and powering of the single specific remote locationconnected to the shorted circuit pair, allowing all other remotelocations to continue to fully function properly.

System 290 was shown in FIG. 29 as being based on splitting the RFsignal in the radio frequency band, such as 2.4 GHz band for IEEE802.11gapplications. Furthermore, a shifter 210 and attenuator 251 wereprovided for each remote location 284. A simpler configuration using asingle shifter 210 and single attenuator 251 is shown as system 300 inFIG. 30. Similar to system 270, the WLAN unit 40 b is connected to athree-way splitter 271 through the antenna port 241 b. Another port ofsplitter 271 is connected to antenna 52 a, and the third port isconnected to attenuator 251, which is in turn connected to a singleshifter 210 a. However, in contrast to the embodiments described above,the shifter 210 a is not connected to couple to a single remote location284, but the shifter 210 a is connected to a multi-port splitter 301.Distinct from splitter 271, splitter 301 is handling a much lowerfrequency, relating to the actual wireless shifter signal that isexpected to be carried over the wire pair 201. In the example describedabove, a frequency band of only 8-30 MHz is required to be supported bythe splitter 271. Each splitter port is provided for each remotelocation, connected to the HPF 221 provided for each such remotelocation 284. A buffer or amplifier may be required between the splitterport and the HPF 221 in order to support an appropriate signal level.

LAN Wiring.

FIG. 31 shows a part of a typical prior art LAN environment 310. Such anetwork commonly uses 10BaseT or 100BaseTX Ethernet IEEE 802.3interfaces and topology, and features a hub/switch 311 as aconcentrating device, into which all devices are connected. Dataterminal Equipment (DTE) devices 312 are connected to the hub/switch 311via a straight-through LAN cable typically containing of four pairsdesignated as 313 a, 313 b, 313 c and 313 d and via connectors 314 a and314 b, each typically containing a plug and a jack. Additionalintermediate connections may exist in the communication link such aspatch panels and wall outlets. The pairs may be UTP or STP. Dataconnectors 314 a and 314 b may be, for example, type RJ-45 connectors,and the pairs 313 may be, for example, part of a Category 5 cabling.Similarly, category 3, 4, 5e, 6, 6e and 7 cables may be equally used.Such configuration is described, for example, in EIT/TIA-568 andEIA/TIA-570. Although FIG. 31 refers to the hub 311 as a concentratingdevice, it is to be understood that any type of device having multiplenetwork interfaces and supporting a suitable connectivity can be used,non-limiting examples of which include shared hubs, switches (switchedhubs), routers, and gateways. Hence, the term “hub” herein denotes anysuch device without limitation. Furthermore, network 310 can be any LANor any packet-based network, either in-building or distributed, such asa LAN or the Internet.

Ethernet communication links based on 10BaseT and 100BaseTX standardsrequire two wire pairs (four conductors) for communication, eachcarrying unidirectional digital data. Since most cables include fourwire pairs, two pairs 313 c and 313 d are commonly wired but not usedfor communication, as shown in FIG. 31. In one non-limiting exampleaccording to the invention, one or both wire pairs 313 c and 313 d areused for carrying the shifted wireless signal from the hub/switch 311location, commonly a communication room or closet, to the DTE 312location over the pre-existing or new LAN cabling. Such a system 320 isshown in FIG. 32. Wire pair 313 c being a spare pair in a LAN cableconnecting pins/circuits 4 and 5 in the connectors 314 a and 314 b isshown as the wired medium. A powering location system 285 a, describedabove as part of system 280 is connected to the cable in the same sideas the Hub/switch 311, and a remote location 284 a, described above aspart of system 280 is connected to the cable in the DTE 312 cable endside. In such arrangement the full functionality of system 280 isretained, wherein the wire pair 313 c is serving as the wire pair medium201 of system 280. In a similar way, wire pair 313 c may contain thewire pair 201 in all the systems described herein. While the poweringlocation 285 a is described as connected in the hub/switch 311 side andremote location 284 a is described as connected in the DTE 312 side, itis apparent that the units may be swapped to have the remote location284 a in the hub/switch 311 side and the powering location 285 a in theDTE 312 side. Furthermore, in the other spare wire pair 313 d connectingpins 7 and 8 may be equally used, as shown in the FIG. 32 wherein thewire pair 313 d connects powering location 285 b and remote location 284b. In one non-limiting example according to the invention, bothwire-pairs 313 c and 313 d are used, each independently connecting apair of locations, such that wire pairs 313 c and 313 d respectivelyconnect powering locations 285 a and 285 b to the respective remotelocations 284 a and 284 b. In such an arrangement, two differentchannels of two distinct wireless signals are carried to the remotelocation, offering increased coverage in the remote site for bothsignals or both channels.

In one embodiment according to the present invention, the two sparepairs 313 c and 313 d are used together to improve carrying of a singleshifted wireless signal. Such a system 325 is shown in FIG. 32 a,showing connecting pins 4 and 5 together in each side of the cable.Similarly, pins 7 and 8 are connected to each other, and hence each suchpair provides a single conductive path, and the two pairs thus provide acommunication/power path using both pairs. Being connected in parallel,the attenuation of the shifted wireless signal as well as the DC powerdrop due to resistance of the wires are substantially lowered, thusimproving both the communication and DC power carrying of the cable. Insome embodiments, the DTE 312 will connect to the LAN cable 313 viaadditional connector 314 c, preferably an RJ-45 jack or plug.

While system 320 was described above based on system 280, wherein thewire pair 313 c (or 313 d or both) are carrying both a DC power signaland the shifted wireless signal using a set of LPF 222 and HPF 221 inboth sides, the split-tap transformer arrangement described above forsystem 279 may be equally used. Furthermore, while system 320 wasdescribed above based on system 280 wherein the wire pair 313 c (or 313d or both) is carrying both a DC power signal and the shifted wirelesssignal, it is apparent that carrying the DC power signal may not beimplemented, and only the shifted wireless signal will be carried asdescribed for system 220 above, for example. While system 320 wasdescribed above as having two fully independent sets of powering/remotelocations, it is apparent that the concept of sharing hardware in thepowering site as described above for systems 290 and system 300 isequally applicable, where either wire pairs 313 sharing the same cable(such as 313 c and 313 d in FIG. 32) or for such pairs in aconfiguration wherein each pair is part of a different or separatedcables.

In one embodiment according to the present invention, the shiftedwireless signal is carried over a phantom channel over LAN cable, asexampled in system 330 in FIG. 33. Carrying a telephone signal over sucha phantom channel is described in patent '303. The phantom channel usesa differential potential between wire-pairs 313 a and 313 b, and isformed by adding the two transformers 331 a and 331 b between thehub/switch 311 and the connector 314 a, as well as adding the twotransformers 331 c and 331 d between the connector 314 b and the DTE312. Transformer 331 a comprises a primary winding 332 a and acenter-tapped secondary winding 332 b, having a center-tap connection333 a. Similarly, transformer 331 b comprises a primary winding 332 dand a center-tapped secondary winding 332 c, having a center-tapconnection 333 b. Transformer 331 c comprises a primary winding 332 gand a center-tapped secondary winding 332 h, having a center-tapconnection 333 c. Similarly, transformer 331 d comprises a primarywinding 332 e and a center-tapped secondary winding 332 f, having acenter-tap connection 333 d. All transformers allow for transparentpassing of the digital data signal between the hub/switch 311 and theDTE 312, hence the Ethernet communication link (either based on 10BaseTor 100BaseTX) functionality is fully retained, commonly via an RJ-34jack 314 c and mating plug. A phantom path is formed between thecenter-taps connections 333 a and 333 b in one side, and thecorresponding center-taps connections 333 c and 333 d. This path is usedby the Powering Location 285 a and the Remote Location 284 a eachlocated and connected to another end of the cable.

While transformers 331 in system 330 were described as being independentand added to the hub 311 and the DTE 312, such transformers may beintegrated into the same enclosure with these units. Furthermore, sincemost such devices have built-in isolation transformers before connectingto the medium, these transformers may be used for forming the phantomchannel as well, thus obviating the need to add any additionaltransformers. While exampled with a phantom channel relating to using aphantom channel over a LAN, it should be apparent that any similarphantom channel may be used. While system 330 was described above basedon system 280 wherein the phantom channel is carrying both a DC powersignal and the shifted wireless signal using a set of LPF 222 and HPF221 in both sides, the split-tap transformer arrangement described abovefor system 279 may be equally used. Furthermore, while system 330 wasdescribed above based on system 280 wherein the phantom channel iscarrying both a DC power signal and the shifted wireless signal, it isapparent that carrying the DC power signal may not be implemented, andonly the shifted wireless signal will be carried as described for system220 above, for example. While system 330 was described above as havingtwo fully independent sets of powering/remote locations, it is apparentthat the concept of sharing hardware in the powering site as describedabove for systems 290 and system 300 is equally applicable for multiplephantom channels carried over separated cables.

A recent technique known as Power over Ethernet (PoE) (i.e., Power overLAN—POL) and standardized under IEEE802.3af, also explained in U.S. Pat.No. 6,473,609 to Lehr et al. titled: “Structure Cabling System”,describes a method to carry power over LAN wiring, using the spare pairsand the phantom mechanism. Such technology, as well as others, may beused to provide power to any of the modems/adaptors described above, inthe case where appropriate cabling (such as CAT.5) is used as the wiredmedium. The powering scheme described above may use this standard aswell as using non-standard proprietary powering schemes.

In Gigabit Ethernet 1000BaseT system, the four pairs in the LAN cableare all used for carrying the data signal. In such configuration, eachtwo pairs may serve as a single phantom channel, hence allowing thecarrying of two distinct shifted wireless signals. The powering schemewill be similarly implemented.

While the invention was exemplified above with regard to using a phantomchannel by carrying a signal differentially between two or more twistedpairs, it is apparent that using such phantom arrangement may be applyto any type of wiring mentioned herein or in any configuration whereintwo pairs of conductors are used. Furthermore, while the invention wasexemplified above with regard to carrying DC or AC power signals andother power related signals over the phantom low frequency band and ashifted wireless signal above this band using FDM, it is apparent thatany type of signal may be used as a substitute to the shifted wirelesssignal and carried over the higher frequency band, being analog ordigital, and being wired or wireless based. In one non-limiting example,UWB is carried over the phantom channel. Furthermore, any of saidsignals, and in particular the wireless based signals, may be carriedover the phantom channel without the presence of the power signal, thusobviating the need for the filters described above.

Hot Spots.

Hot spots are known as locations providing wireless access to theInternet to mobile computers such as laptops and PDAs (Personal DigitalAssistant). The wireless access is commonly based on WiFi such asIEEE802.11g. Hotspots are often found near or in restaurants, trainstations, airports, cafes, libraries, universities campuses, schools,hotels, and other public places. In some locations a payment is requiredin order to access the Internet, while in other locations free access isprovided. In most cases, however, some type of authentication isrequired.

In many cases, a hotspot application makes use of pre-existing wiring.In many cases, an existing telephone wire-pair that was primarilyinstalled for carrying an analog telephone signal (POTS—Plain OldTelephone Service) is used to carry the data to the required location. Atypical system 340 is shown in FIG. 34, showing a remote site 347 and acenter site 348 locations connected via such a telephone wire pair 341.In one embodiment the telephone wire pair is a ‘subscriber line’ (i.e.,Local-Loop, Subscriber Loop, ‘Last Mile’) wire pair, connecting asubscriber site 347 to a telephone exchange (e.g. CO—Central Office,telephone switch) site 348. Such pairs are carried as cable bundleseither underground or over the ground over telephone poles, and enterthe subscriber building through a connection box/junction box, typicallymounted in the outside wall of the building or in the basement. Inanother embodiment the telephone wire pair is inside a building (e.g.enterprise, factory, hotel, hospitals, dormitories, campuses,universities, residential house, office building, multi-storiesbuilding, warehouse, MDU—Multiple Dwelling Unit and so forth), commonlyconnecting between a central location 348, typically a communicationroom or communication closet, and a room or rooms in the building. Inmany applications, the central site 348 also comprises a PBX or PABX andgeneral communication to a network (WAN or LAN) external to thebuilding, such as a PSTN or CATV. Typically, outlets are used forconnecting to the telephone wire-pair in the building. In one embodimentthe remote site 347 is a telephone-oriented location such as a publictelephone booth.

In order to enable a digital data communication over the telephonewire-pair, typically a dedicated DSI, (Digital Subscriber Line)technology is employed, such as ADSL (Asymmetric Digital SubscriberLine). ADSL technology is known in the art to carry digital data over asingle telephone wire pair 341 (using for example ADSL per ANSI T1.413,G,DMT per ITU G.992.1, G.Lite per ITU G.992.2, ADSL2 per ITU G.992.3 andADSL2+ per ITU G.992.5 standard). Other ADSL derivatives, other DSLtechnologies such as VDSL, (Very high bit Rate Digital Subscriber Line),HDSL and SHDSL, as well as their derivatives and flavors may be equallyemployed. In most DSL systems, a DSI, modem 344 (such as ATU-C: ADSLTerminal Unit—CO) is connected to the center side of the wire pair 341,and a mating DSL modem 345 (such as ATU-R: ADSL Terminal Unit—Remote) isconnected to the other end in a point-to-point connection. The ATU-Runit 345 is powered through an internal (or external) power supply fedfrom the AC power grid via AC power plug 229 a. The digital data to andfrom the wire pair 341 is coupled to the WAP unit 346, commonly by anEthernet (such as 10BaseT or 100BaseT) connection. The wirelesscommunication in the remote site 347 is provided by the Wireless AccessPoint (WAP) unit 346, which includes an antenna 52 for radio interface.Similarly, any other type of WLAN unit 40 may be employed. The WAP unit346 is powered through an internal (or external) power supply fed fromthe AC power grid via AC power plug 229 b.

The center site 348 is connected to the Internet 342 via a broadbandunit 343, which connects to the Internet using any type of medium suchas wired or wireless, such as through PSTN, CATV, fiber or BWA. The datato and from the Internet is coupled to the wire pair 341 using the DSLmodem 344, which may be part of a DSLAM (DSL Access Multiplexer).

The disadvantages described above are applicable to the arrangement 340shown in FIG. 34. A product family named “LoopStar™ Span-Powered G.SHDSLWi-Fi solution” available from ADC Telecommunications, Inc. fromMinneapolis, Minn. USA, offers an improved solution wherein thetelephone wire pair concurrently carries a DC power signal for remotelypowering the remote site 347, thus obviating the need for a local ACpower supply through AC plugs 229 a and 229 b. However, a hazardousvoltage of 130 VDC is used for remotely powering (‘span-powering’) theremote site 347, required in order to feed both the power-hungry DSLmodem 345 and the WAP unit 346 and for providing a long enough distanceover the telephone wire pair 341.

Any of the above described systems employing a wire pair may as well beimplemented for such hotspot application, wherein the wire pair 201 (orplurality of such wire pairs) is substituted with a telephone wire pairsuch as 341. Such implementation may only require changing the equalizer206 of system 260 to be adapted to the characteristic of a telephonewire-pair in general or specifically to the telephone wire pair 341 tobe used. Similarly, protection 215 of system 260 may need to be adaptedto the specific environment. As a non-limiting example, long and outdoorwire pair 341 may require hardened lightning protection (known asprimary lightning protection) while in-building (in-door) applicationmay require only a secondary lightning protection. System 350 shown inFIG. 35 a is an example of adapting system 250 shown in FIG. 25 forhot-spot application. The telephone wire pair 341 is used as a specificexample for the general wire pair 201. The WAP unit 346 is moved fromthe remote site 347 to the center site 348, wherein it replaces thegeneral WAN unit 40 b. A more general system 355 is shown in FIG. 35 b,shows a general powering location 285 a and a general remote location284 connected via the telephone wire pair 341 as a specific example or awire pair 201. As explained above, such configuration allows the use ofa lower powering voltage such as 48 VDC.

Cellular.

According to one embodiment of the invention, frequency shifting is usedto improve coverage in a building to a communication tower, such ascommunication between a cell phone and base-station, similar to thesystem 180 described above, however using a wired connection between thefrequency shifters. Adaptation of system 220 for such application isshown as system 360 in FIG. 36. A cell phone 182 is shown in building171 b, communicating with a base-station over communication tower 181over communication link 152 e. In order to improve the in-buildingreception, two frequency shifters 210 are provided, each connected tothe ends of the wire pair 201. A frequency shifter 210 a is provided,preferably located in the building in a location wherein a reasonablesignal and good communication is available with the tower 181 viaantenna 52 a. Optimally, the frequency shifter should be located in aplace where there is a clear and non-interfered LOS to the tower 181.The signal from the tower 181 via link 152 e is shifted to anotherfrequency and retransmitted over the in-building wire pair 201 tofrequency shifter 210 b having antenna 52 b covering area 151 e, linkingwith the cellular device 182 via link 152 f. Any one of the systemsdescribed above such as 230, 240, 245, 270, 275, 279, 280, 290, 300, 320and 325 and their derivatives can equally be used for such cellularapplication, in order to allow cellular reception and coverage inlocations having poor or no cellular communication coverage. In sucharrangement, the cellular frequency band is used instead of theIEEE802.11g frequency band exampled above.

Plug-in.

Similar to the above discussion regarding enclosing the systems in aplug-in form or as an outlet, one or both sides connected to the wirepair 201 as part systems described above and their derivatives may behoused as an outlet plug-in enclosure. In one embodiment according tothe invention, a plug-in into an AC power outlet is used as suchenclosure. A mechanical outline of such a plug-in unit 370 is generallyshown in FIG. 37 a, with a perspective rear view in FIG. 37 c and frontview in FIG. 37 b. A North-American style AC power outlet 191 is shown,having two power sockets 192 a and 192 b. The frequency shifter 210, forexample, enclosed as plug-in module 370 is shown to have two powerprongs 193 a and 193 b respectively mating with sockets 192 a and 192 b,providing electrical connection as well as mechanical support, enablingthe plug-in unit 370 to be easily attached to the outlet 191. Antenna 52a is shown, as well as a channel selecting mechanical rotary switch 139a having 11 positions for selecting one out of the 11 channels of theIEEE802.11g. In the example shown, rotary switch 139 b controlling the‘A’ sub-system channel is set to channel 6. The power connection viaprongs 193 a and 192 b may serve as AC plug 229 above and used to supplyAC power to the unit 370 for powering its internal circuits, preferablyvia a power supply including an AC/DC converter, for converting the 110VAC 60 Hz power from the outlet 191 to the DC voltage or voltagesrequired for proper operation of the frequency shifter 210.

While the shifter 210 was described as a plug-in module to an AC poweroutlet, it is apparent that a frequency shifter may be equallyplugged-in to any outlet, being an AC power, telephone, CATV, or LAN(such as Structured Wiring based on Category 5, 6 or 7 wiring) outlet.While the shifter 210 was described as being both powered from andmechanically supported by the attached AC power outlet, such couplingmay be only for power feeding or only for mechanical support.

A mechanical outline of a plug-in unit 375 for attaching to a LAN outletis generally shown in FIG. 37 d, with a perspective rear view in FIG. 37e. A typical LAN outlet 196 is shown, comprising a LAN connector 197such as RJ-45 jack. The frequency shifter 284, for example, enclosed asplug-in module 375 is shown to have an RJ-45 plug 198 respectivelymating with LAN connector 197, providing electrical connection as wellas mechanical support, enabling the plug-in unit 375 to be easilyattached to the outlet 196. Antenna 52 a is shown, as well as a channelselecting mechanical rotary switch 139 a, having 11 positions forselecting one out of the 11 channels of the IEEE802.11g. In the exampleshown, rotary switch 139 a controlling the ‘A’ sub-system channel is setto channel 6. In one embodiment according to the invention, the LANwiring connected to the outlet 196 via jack 197 carries a power signal,either using a proprietary implementation or for example according toPoE (Power over Ethernet) IEEE802.3af standard, explained above. Theplug-in module 375 serves as a PD (Powered Device) and is powered fromthe LAN wiring, typically via DC/DC converter, as described above.

Since the RJ-45 jack may cover the LAN jack 197 thus obviating theconnection of other LAN devices, an RJ-45 jack 378, implementingconnector 312 c above, may be used as a transparent ‘pass-through’ pathretaining the capability to connect LAN units to the cable. Such aplug-in module 376 is shown in FIG. 37 f.

Telephony.

The term “telephony” herein denotes in general any kind of telephoneservice, including analog and digital service, such as IntegratedServices Digital Network (ISDN).

Analog telephony, popularly known as “Plain Old Telephone Service”(“POTS”) has been in existence for over 100 years, and is well designedand well engineered for the transmission and switching of voice signalsin the 300-3400 Hz portion (or “voice band” or “telephone band”) of theaudio spectrum. The familiar POTS network supports real-time,low-latency, high-reliability, moderate-fidelity voice telephony, and iscapable of establishing a session between two end-points, each using ananalog telephone set.

The terms “telephone”, “telephone set”, and “telephone device” hereindenote any apparatus, without limitation, which can connect to a PublicSwitch Telephone Network (“PSTN”), including apparatus for both analogand digital telephony, non-limiting examples of which are analogtelephones, digital telephones, facsimile (“fax”) machines, automatictelephone answering machines, voice (e.g. dial-up) modems, and datamodems.

The terms “data unit”, “computer”, and “personal computer” (“PC”) areused herein interchangeably to include workstations, Personal DigitalAssistants (PDA) and other data terminal equipment (DTE) with interfacesfor connection to a local area network, as well as any other functionalunit of a data station that serves as a data source or a data sink (orboth).

In-home telephone service usually employs two or four wires, to whichtelephone sets are connected via telephone outlets.

While the invention has been exampled above with regard to carryingpower and shifted wireless signal over the same wire pair using FDM, itis apparent that any other type of signal can be carried frequencymultiplexed over the wire pair, such as analog or digital signals. Inone embodiment according to the invention, the signal carried is aservice signal in a building such as an analog telephone signal (POTS)carried over the telephone wire pair in a building that was primarilyinstalled for carrying the telephone signal.

The system 380 shown in FIG. 38 is based on system 240 shown in FIG. 24adapted to carry an analog telephone signal instead of a power signalover the medium. The medium 382 is a telephone wire pair substitutingthe general wire pair 201 and is either new or pre-existing, and may beprimarily installed to carry the analog telephone signal. However, theinvention also applies to the case where the wire pair 382 is any othertwo wired or two conductors, such as described above with regard to wirepair 201. In the shifted wireless signal path, HPFs 221 a and 221 b usedto block the DC power signal are respectively substituted with HPFs 385a and 385 b. HPFs 385 a and 385 b are aimed to transparently pass ashifted wireless signal 393 and to stop or reject other signals that mayshare the same wire pair 382 such as an analog telephone signal 391 andADSL signal 392. In one embodiment, a passive filter 385 a is used,comprising two capacitors pairs, one pair including capacitors 228 baand 228 ca, and the other pair including capacitors 228 da and 228 ea,each pair connected in series to each of the two conductors carrying thesignal. An inductor 223 ea in connected in parallel to the signal pathconnected to the capacitor pair connection points. In one exemplaryimplementation, the capacitors 228 were selected all to be 150 pF andthe inductor 223 ea was selected to be 1.8 μHy. Similarly, a matingpassive filter 385 b is used, comprising two capacitors pairs, one pairincluding capacitors 228 bb and 228 cb, and the other pair includingcapacitors 228 db and 228 eb, each pair connected in series to each ofthe two conductors carrying the signal. An inductor 223 eb in connectedin parallel to the signal path connected to the capacitor pairconnection points. In one exemplary implementation, the capacitors 228were selected all to be 150 pF and the inductor 223 eb was selected tobe 1.8 μHy.

The analog telephone signal may be provided from any type of analogtelephone signal source such as PBX, PABX, exchange or the PSTN network,or may be sourced from a VoIP or digitally based telephony through anappropriate gateway or adaptor. The coupling to the medium 382 mayinvolve connectors 388 such as telephone plug 388 d and jack 388 b. Inone example, RJ-11 type is used as the telephone connectors 388,commonly used in North America. However, any standard or non-standardconnectors may be equally used. LPFs 383 a and 383 b are used as asubstitute to the DC pass filters 222 a and 222 b, and are designed topass the analog telephone signal 391 (and the ADSL signal 392, ifrequired), and stop or reject the shifted wireless signal 393. In oneembodiment, a passive filter 383 a is used, comprising two inductorspairs, one pair including inductors 223 aa and 223 ba, and the otherpair including inductors 223 ca and 223 da, each pair connected inseries to each of the two conductors carrying the signal. A capacitor228 aa is connected in parallel to the signal path connected to theinductors pair connection points. In one exemplary implementation, thecapacitor 228 aa was selected to be 560 pF, the inductors 223 aa and 223ca were selected to be 2.2 μHy, and the inductors 223 ba and 223 da wereselected to be 3.9 μHy. Similarly, a mating passive filter 383 b isused, comprising two inductors pairs, one pair including inductors 223ab and 223 bb, and the other pair including inductors 223 eb and 223 db,each pair connected in series to each of the two conductors carrying thesignal. A capacitor 228 ab is connected in parallel to the signal pathconnected to the inductors pair connection points. In one exemplaryimplementation, the capacitor 228 ab was selected to be 560 pF, theinductors 223 ab and 223 cb were selected to be 3.9 μHy, and theinductors 223 bb and 223 db were selected to be 2.2 μHy. The telephoneservice is terminated in a telephone set 384, which may represent anydevice capable of connecting to an analog telephone signal, non limitingexamples are facsimile, dial-up modem, and answering machines. Theconnection to the telephone set 384 may make use of the telephoneconnectors 388 set, such as telephone plug 388 c and telephone jack 388a. In one embodiment, all the functions in the location (‘center’location/site) connected to the PBX 381, are enclosed or integrated intoa single function or a single enclosure 386. Such a unit 386 comprisesthe shifter 210 a, the HPF 385 a, the LPF 383 a, and telephone connector388 b. Similarly, the remote site may be referred to as a singlefunction or enclosure 387, comprising shifter 210 b, HPF 385 b, LPF 383b and telephone connector 388 a.

While system 380 and other systems herein are described as based onpoint-to-point involving only two units, each connected to opposite endsof the wire pair 382, it is apparent that any topology and any number ofunits may share the same wire pair 382, as described above for system230.

The various signals and their corresponding frequency bands are shown ingraph 390 in FIG. 39. Owing to FCC regulation in North America regardingradiated electromagnetic emission, the usable frequency band isconsidered to extend up to 30 MHz. Hence, a spectrum allocation for abaseband signal occupying 22 MHz may be between 8 MHz and 30 MHz(centered around 19 MHz), as shown in curve 393 being part of graph 390in FIG. 39, illustrating the various power levels allocation along thefrequency axis 394. Such allocation allows for ADSL signal 392 using the100 KHz (or 25 KHz) to 1.1 MHz and the POTS signal curve 391.

System 245 shown in FIG. 24 a may similarly be adapted for carrying ananalog telephone signal instead of a DC power signal. Such a system 400is shown in FIG. 40, and is based on three telephone wire pairs 382 a,382 b and 382 c. The wire pairs 382 a, 382 b and 382 c respectivelyconnect the center location to the remote locations 387 a, 387 b and 387c (described above as part of system 380), which are respectivelyconnected or connectable to analog telephone sets 384 a, 384 b and 384c. In the center location, the HPF 221 a in system 245 is substitutedwith an HPF 385 (described above), and the DC power relating units suchas plug 229, Power Supply 224, and LPF 222 a are substituted with PBX381, coupled to the wire pairs 382 via LPF 383 described above.

System 275 shown in FIG. 27 a may similarly be adapted for carrying ananalog telephone signal instead of a DC power signal. Such a system 410is shown in FIG. 41, and is based on a telephone wire pair 382connecting the center and remote locations. Similar to the above, HPFs221 a and 221 b are respectively replaced with HPFs 385 a and 385 b, andthe DC power related parts are omitted and replaced with the PBX 381 (orconnection thereto) and LPF 383 a in the center location and LPF 383 band telephone set 384 in the remote location. In a similar way, system279 is adapted to form system 420 shown in FIG. 42, using wire pair 382and to carry an analog telephone signal instead of the DC power signal.

While system 410 shown in FIG. 41 was described as focusing on improvingthe coverage, it is apparent that this system also carries wired databetween WLAN units 40 a and 40 b over the wire pair 382. It is apparentthat such a system as well as any similar wired-medium based system maybe used only for exchanging data between two wired remote data units,without any radio communication link involved. Such a system 415 isshown in FIG. 41 a, and may be considered as a simplified version ofsystem 410. Two data-unit 416 a and 416 b, which are pictoriallyexampled as a personal computer, but may be any DTE (Data TerminalEquipment), are respectively connected via WLAN unit wired ports 41 aand 41 b (e.g., Ethernet 10/100BaseT per IEEE802.3 or USB) to therespective WLAN units 40 b and 40 a. The two computers 416 cancommunicate over the wire pair 382. It is apparent that suchcommunication may also take place in system 410. Such a system may be areplacement to other technology used to carry data over wiring ingeneral and over a telephone wire pair in particular, such as DSL andVDSL.

While in the embodiments described above the same analog telephonesignal is distributed to all remote locations, it is apparent that in asimilar way, multiple distinct analog telephone signals may be carriedto multiple locations. Such arrangement is suitable to any environmentwhere multiple distinct telephone wire pairs are distributed from asingle center location to multiple remote locations, such as in any PBXenvironment, typically found in hotels, multi-unit dwelling, apartmentbuilding, dormitories and residential buildings employing a PABX/PBX.Such a system 430 is shown in FIG. 43, based on system 290 shown in FIG.29. System 430 is based on three telephone wire pairs 382 a, 382 b and382 c respectively connecting remote locations 387 a, 387 b and 387 c tothe center location, and allowing respectively telephone sets 384 a, 384b and 384 c to connect to the center location via the remote locations387. The shifted wireless signal is carried similarly to system 290above, wherein the HPFs 385 a, 385 b and 385 c are respectively used toconnect to the telephone wire pairs 382 a, 382 b and 382 c. However,three distinct telephone service signals are sourced from the PBX 431via ports 432 a, 432 b and 432 c. The ports are respectively connectedto LPFs 383 a, 383 b and 383 c, enabling three distinct telephonesignals to be carried to the telephone sets 384 a, 384 b and 384 c. Forexample, each such telephone set can connect to make a differenttelephone conversation, independently from the other telephone sets.System 440 shown in FIG. 44 offers the same telephony functionalitybased on handling of the shifted wireless signal as per system 300 shownin FIG. 30.

In the above embodiments the telephone signal 391 and the shiftedwireless signal 393 are carried using FDM over the single wire pair 201or 382. In the general case shown as part of system 450 in FIG. 45, thecoupling to the wire pair 382 involves two LPFs 383 a and 383 brespectively for the center site and for the remote site, respectivelyhaving ports 455 a and 455 b for connecting to PBX 381 and telephone set384. Similarly, the frequency shifters are coupled to the wire pairusing two HPFs 385 a and 385 b respectively for the center site and forthe remote site, respectively having ports 456 a and 456 b forconnecting to frequency shifters 210. In many applications, such as thehot-spot environment described above, it is beneficial to alsoconcurrently carry a power signal over the same wire pair, for poweringpart or all of the remote location. According to one embodiment shown assystem 450 in FIG. 45, the FDM is used to also carry the power signal.Such powering system is described in the '353 patent, and involvescarrying the power signal as an AC power signal, carried over a distinctfrequency band. For example, the AC power may be using any one of a fewfrequencies in the 10 KHz-100 KHz frequency band, being above thetelephone band 391, yet below the ADSL band 392. For example, a 20 KHzAC power signal may be used. System 450 shows such an arrangement,wherein AC power is derived from the AC power grid using AC power plug229 a, feeding an AC/AC converter for generating the 20 KHz AC powersignal. This AC power signal is fed to the wire pair 382 a through BPF(Band Pass Filter) 451 a via port 457 a. BPFs 451 a and 451 b aredesigned to pass the AC power signal and to stop/reject both the analogtelephone and the shifted wireless signals. In the case of the presenceof ADSL signal 392 or any similar signal, the LPFs 383 a and 383 b maypass the ADSL signal, while all other filters block this frequency band.In the remote side, the BPF 451 b extract the AC power signal, and feedsAC/DC converter 453, which it turn sources DC power signal via port 457b. The resulting DC power signal is feeding the load 227, which mayinclude the frequency shifter 210 and any other equipment in the remotelocations. The functions that are in charge of accessing the wire pair382 a are forming filters set 458 in the center site, which includes BPF451 a, HPF 385 a and LPF 383 a. Similarly, the functions that are incharge of accessing the wire pair 382 a form the group 459 in the remotesite, which includes BPF 451 b, HPF 385 b, AC/DC 453 and LPF 383 b.

Hot-Spot.

Systems 350 and 355 shown above in FIGS. 35 a and 35 b respectivelyteach a hot-spot application, where DC power and shifted wirelesssignals are carried over a single telephone wire pair 341. System 460shown in FIG. 46 further allows for carrying a power signal from thecenter to the remote site over the same telephone wire pair 382. The ACpower mechanism described in system 450 (of FIG. 45) is employed,allowing for AC power to be carried from the power source 229 a and theAC/AC converter 454, through BPF 451 a to the wire pair 382, which isconnected to the remote location BPF 451 b. The extracted AC power is DCconverted by AC/DC converter 453, and the resulting DC power signal isshown to power any power consuming elements such as WLAN unit 40 a andshifter 210 b, as well as any additional active circuits.

The parts of system 460 located in the powering location may be groupedinto a single device 490 shown in FIG. 49. A connector 491 is providedfor connecting to the wire pair 382, and a telephone connector 492 isprovided for connecting to the PSTN 381. The broadband wait 343 connectsto the Internet 342 via connector 493, and the AC powered is providedusing the power connector 494. The AC/DC power supply 224 is fed fromthe AC supply power and feeds all the circuits within the device 490.

While system 460 was shown as interfacing the Internet 342 (or any otherdata network) and the PSTN 381 via different connections, in somehot-spot and other applications, a single connection may be used forboth data and analog telephony, for example using a single telephonepair carrying both ADSL and analog telephony as known in the art. Asystem 470 shown in FIG. 47 refers to such a configuration. The system470 is connected to a PSTN network 471 via a telephone wire paircarrying data as ADSL and analog telephony using FDM as shown in graph390. ADSL filter 472 (typically an HPF) passes the ADSL signal to theADSL modem 345, which in turn exchanges data with the WAP 346. Theanalog telephone signal is filtered by LPF 383 a and coupled to thetelephone wire pair 382 (which is distinct from the wire pair 473). Inthe remote side, the analog telephone signal is filtered by LPF 383 band coupled to telephone set 384 via the telephone connectors 388 a and388 c and connection 455 b.

The parts of system 470 located in the powering location may be groupedinto a single device 495 shown in FIG. 49 a. A connector 491 is providedfor connecting to the wire pair 382, and a telephone connector 492 isprovided for connecting to the PSTN 381. The broadband unit 343 connectsto the Internet 342 via the telephone connector 492, and the AC poweredis provided using the power connector 494. The AC/DC power supply 224 isfed from the AC supply power and feeds all the circuits within thedevice 495.

While the invention has been described above with regard to a telephonewire pair, it is apparent that a spare pair in a LAN cable or usingphantom channel may as well be used as the wired medium in a similar wayas described in systems 320, 325 and 330 above. The powering relatedcircuits should be substituted with an analog telephone signal handlingin a similar way to the system described above.

In-Building Telephone.

The telephone wire-pair 382 may also contains an in-building telephonewire pair. Typically such in-building telephony wiring comprises asingle wire-pair or two wire-pairs (for supporting two distincttelephone lines/numbers). An example is shown as system 480 in FIG. 48a, wherein the in-building telephone wiring contains three telephonewire-pairs 484 a, 484 b and 484 c, connected in series (known as‘daisy-chain’ configuration). Other topologies such as star (i.e.home-run) and other mixed topologies are also common. Access to thetelephone wire pair 484 is available by means of telephone outlets,comprising a telephone connector. In the example of system 480, threeNorth-American type telephone outlets 485 a, 485 b and 485 c are shown,respectively mounting telephone connectors (typically RJ-11 jack) 489 a,489 b and 489 c. A telephone wire pair segment 484 c connects outlets485 c and 485 b. Similarly, a telephone wire pair segment 484 b connectsoutlets 485 a and 485 b. The connection between the in-building wiringand the external wiring 483 (the ‘local loop’ or the ‘subscriber line’)that connects to the PSTN 471 (typically to a near central Office) isperformed in a connection fixture known as the Junction-Box or NID 482(Network Interface Device), typically serving as the Demarcation-Pointbetween the telephone service provider and the building owner. In thecase of a single family home, the NID 482 is commonly mounted on a walloutside the building or in the basement. In the case of multi-unitdwellings, office buildings, and factories the NID 482 may be installedin a dedicated communication room or closet. A telephone wire pair 484 ais shown to connect the outlet 485 a to the NID 482.

In the case where the in-building telephone wire pair 484 is used as thetelephone wire pair 382 in the above described embodiments, theconnection to the wiring commonly employs connecting to the telephoneconnector 495 in the wall mounted outlet 485. In the system 480, tworemote locations 387 a and 387 b are shown, each comprising thefunctions described above for the relevant sub-system being part ofsystem 380. The remote locations 387 a and 387 b respectively includeantennas 52 a and 52 b, and are shown connected to the respectivetelephone sets 384 a and 384 b, and use the respective ports 481 a and481 b for connecting to the telephone outlets. In such a system 480 thetelephone service functionality is fully retained, since the telephonesets 384 are effectively connected to the PSTN 471 as if no hardware wasadded. However, the in-building telephone wiring doubles as a backbonefor carrying the shifted wireless signal from one point (e.g., one room)to another point in the building (e.g. another room). Hence, similar tothe benefits of the systems described above, the effective coverage ofthe wireless signal is increased; and allows removal of ‘dead spots’ orareas of poor wireless reception. In another embodiment, one of theremote locations 387 is located in the home having optimum reception ofan external wireless signal such as a cellular signal, as explained withregard to system 360 above, wherein the in-building telephone wire pair484 serves as the connecting medium 201. Similar to the above, thesystem 480 improves the cellular coverage in the building; however theneed for installing new cabling is obviated by using the existingtelephone wire pair 484.

While system 480 demonstrates application of system 380 for in-buildingenvironment, wherein the telephone wire pair 484 in the building servesas the telephone wire-pair 382 and is connected to via outlets, allother systems described above may as well be similarly implemented. Forexample, system 460 may be implemented where all the units in the centerlocation that are connected to one end of the wire pair 382 (left sideof the Figure) may be integrated into a single enclosure and connectedto one outlet, while all the remote location parts will be integratedinto a second device that will be connected to another outlet in thebuilding.

While system 480 improves the wireless communication and coverage fromone location in the building to another location in the building, thedescribed mechanism may also support enabling external wirelesscommunication to reliably communicate with units in the buildings, thusovercoming at least some of the obstacles described above. Suchadvantage may be obtained by installing a frequency shifter in the NIDitself, as shown for system 486 in FIG. 48 b. In this system 486, acenter location 386 (shown above in FIG. 38 as part of system 380) isinstalled in the NID 482, between the in-building telephone wire pair484 a connected via port 388 c and the PSTN 471 via the connection 483.The center location 386 includes antenna 52 c for communicating withexternal antenna 52 d of WLAN unit 40 b, which may be a hot-spot, forexample. The radio signal received via the wireless communication link152 b is down frequency shifted and transmitted over the in-buildingtelephone wire pair 484 to remote locations 387 a and 387 b, andvice-versa for a radio signal received by one of the remote locations387 and communicated to the external center location 386. In this way,the radio signal need not penetrate the building walls, but is ratherpenetrating the house via telephone wiring of the house. Similarly, thecellular communication with a cellular tower or cellular antenna 181(via radio communication link 152 e) may be significantly improved, asshown for system 488 in FIG. 48 c and discussed above regarding system360 in FIG. 36. The center location 386 located in the NID may begrouped into a single device 496 shown in FIG. 49 b.

It is apparent that systems 460 and 470 may be implemented in a similarway, wherein part of the system is located in the NID, received by wireddigital data (e.g., via fiber, ADSL or VDSL), and includes a WAP 346 fortransmitting and receiving wirelessly. However, the actual radiotransmission and reception is inside the building using devicesconnected to the telephone outlets. In this configuration the telephoneservice provider can access, install and remotely manage the equipmentlocated in the NIL), but still enable a wireless coverage in the houseusing the existing telephone wire-pairs. Furthermore, the in-buildingdevices may be powered from the NID.

DC Powering.

The POTS system involves using the DC power signal over the telephonewire pair for ‘Off-Hook’ and ‘On-Hook’ signaling, as well as forpowering the telephone set from the CO or PBX/PABX. Hence, carryingadditional power over the same telephone wire pair requires using adistinct frequency band above the analog telephone signal (typically 0-4KHz), thus an AC power signal is contemplated, as described above in thearrangement 450. The arrangement was described as using two filter setsdesignated as 458 for the powering location and 459 for the remotepowered site.

US Patent Application Publication '1305 teaches a system and method forcarrying a DC power signal over a telephone wire pair, withoutinterfering with the ‘On/Off Hook’ signaling. The concept is based oncarrying the ‘Off/On-Hook’ signals not as DC signals, but ratherconverting them into non-DC signals such as tones, and thus freeing theDC frequency for carrying DC power. The tones representing the ‘On/OffHook’ signals are generated at the telephone set interface, carried overthe telephone wire pair, and re-converted to DC signals at the portconnecting to a CO or PBX, and thus are transparently carried over thesystem. In general, the embodiments described in Publication '1305 maybe used in conjunction with the present invention, wherein thephonelines modem PNC (designated as numeral 93 in Publication '1305)used for transceiving digital data over the telephone wire pair issubstituted with the shifter 210 for coupling a shifted wireless signalto and from the wire pair.

The remote location arrangement of a system implementing a DC poweringscheme according U.S. Patent Application Publication '1305 is shown asDC-Sink arrangement 505 in FIG. 50 b, which may be used as a substituteto arrangement 459 of FIG. 45. The arrangement 505 provides a port 455 bfor connecting an analog telephone set 384. The DC power and thetelephone related signals are passed from the wire pair 382 a throughthe LPF 383 b and the telephone coupler 509 (designated as numeral 36 inPublication '1305), mainly comprising a current limiter. The Off-HookDetector 498 (designated as numeral 41 in Publication '1305) detects thehook state of the telephone set connected to port 455 b, and notify thisstatus (or its changes) to the Off-Hook Transmitter 499 (designated asnumeral 42 in Publication '1305), which in turn send transmit thisstatus information using a non-DC signal such as tones to the wire pairs382 a. The Load coupler 508 (designated as numeral 31 in Publication'1305) pass the DC power signal to the DC/DC converter 225 (designatedas numeral 76 in Publication '1305) for converting to the voltagesrequired in the remote location, and feed the load 227 via port 457 b.Similar to the above, an HPF 385 b isolates the data signals, andsubstantially blocks the power and analog telephony signals.

The center/powering location arrangement of a system implementing a DCpowering scheme according to U.S. Patent Application Publication '1305is shown as DC-Source arrangement 501 in FIG. 50 a, which may be used asa substitute to arrangement 458 of FIG. 45. The arrangement 501 providesa port 455 a for connecting a CO/PBX 381. The non-DC components of thetelephone signal in this port are passed to and from the telephone wirepair 382 via the AC Pass/DC Stop 506 (designated as numeral 34 inPublication '1305). The signals representing the hook status from theremote location 505 are carried over the wire pair 382 a (e.g., tones)and are received by the Off-Hook receiver 502 (designated as numeral 44in Publication '1305). The status is fed to the Off-Hook simulator 503(designated as numeral 43 in Publication '1305), which represent theappropriate DC load via the DC Pass/AC Stop 504 (designated as numeral35 in Publication '1305). DC power is received from the AC/DC powersupply 454 (fed from the AC plug 229 a) via port 457 a, and is insertedto the telephone wire pair 382 a via Power Supply Coupler 507(designated as numeral 33 in Publication '1305) and the LPF 383 a. Theshifted wireless signal is coupled between the port 456 a and the wirepair 382 a via HPF 385 a.

Replacing the units 458 and 459 of system 450 with the respective units501 and 505 enables the same functionality of carrying power, telephoneand shifted wireless signals over a single wire-pair, however using a DCpowering scheme over the medium. Such substitution can be implemented inany of the systems described above. A non-limiting example is system 510shown in FIG. 51, which is based on system 460 shown in FIG. 46 above.In the powering site, the AC/AC power supply 454 is replaced with a DCpower supply 224. The filters set BPF 451 a, HPF 385 a and LPF 383 a,containing filters set 458, is substituted with the DC Source unit 501,thus enabling inserting DC power to the remote end 511 a. In the remotesite 511 a, the signals separations filters set 459 containing LPF 383b, HPF 385 b and the BPF 451 b, as well as AC/DC 453 device, aresubstituted with a DC Sink device 505.

Power and Multiple Remote Locations.

System 440 was described above for supporting multiple remote locationsusing a centralized shifter 210 a using a splitter 301. Suchmulti-remote location environments may also be used to also power theremote locations via the wire pairs. An AC powering scheme of suchconfiguration is shown as system 520 in FIG. 52. Similar to the abovedescription regarding arrangement 450, each telephone wire pair 382 alsoconcurrently carries an AC power signal using FDM. The AC power signalis supplied by AC/AC Power Supply 454 through port 457 a, and is coupledto the wire pairs 382 a, 382 b and 382 c via the respective BPF 451 a,451 b and 451 c. Remote locations 521 a, 521 b, and 521 e are connectedto the respective wire pairs 382 a, 382 b and 382 c, and are connected(or connectable) to the respective telephone sets 384 a, 384 b and 384c. Each such remote location 521 comprises the circuits similar to theremote site shown as part of system 460 shown in FIG. 46, including BPF451, HPF 385 and LPF 383, all connected to the respective wire pair 382,A shifter 210, attenuator 251, splitter 271, antenna 52 and WLAN unit40, are all coupled to the HPF 385. Power Supply AC/AC 453 connected tobeing powered from the BPF 451 (as in FIG. 47), and powers the remotelocation power-consuming elements. The telephone set 384 is connected tothe LPF 383.

Similarly, a DC powering scheme may be used, as described for a singleremote location in system 510. Such a system 530 is shown in FIG. 53. Inthe powering site, the DC source unit 501 replaces the filters setincluding the HPF 385, LPF 383 and BPF 451. Similarly, in each remotesite 531 a DC Sink unit 505 (of FIG. 51) replaces the correspondingfilters set.

Telephone Plug-In Unit.

In the case wherein the telephone wire pair 382 is an in-building wiringaccessed via telephone outlet, the remote location device or thecenter/powering device may be enclosed in plug-in form as describedabove. Such plug-in unit 540 is shown in FIG. 54 a, also showing atypical North-American type telephone outlet 541 having an RJ-11 jack542 for connecting to the in-wall telephone wire pair. The unit 540 mayenclose part or all of any of the above systems or sub-systemsconnecting to the telephone wire pair 382. The unit 540 electricallyconnects to the outlet 541 via RJ-11 plug 544 shown in FIG. 54 b. Theunit 540 may also be mechanically attached to the outlet 541. Antenna 52a and rotary switch 139 a are shown as part of the plug-in unit 540. Inorder for allowing a telephone set 384 to couple to the telephone signalcarried over the wire pair 382, a RJ-11 jack connector 543 is provided,implementing connector 388 a or port 455 b, for example.

CATV/Coaxial Cable.

While the invention was exemplified above with regard to using aPOTS-oriented telephone wire pair 382 and with regard to carrying aPOTS-oriented analog telephone signal 391, it is apparent that otherwiring types, as well as carrying other service signals, may be equallyused, including any PAN, LAN and WAN wiring. In one or more embodimentsaccording to the present invention, a coaxial cable 568 is used as theconductive medium. The superior communication characteristics of acoaxial cable can result in longer distance and better communicationperformance than other wiring mediums. In one or more embodimentsaccording to the present invention, the service signal carried togetherwith the shifted wireless signal is CATV-oriented channels service. Atypical frequency band allocation used in a CATV environment inNorth-America over a coaxial cable is shown as graph 550 in FIG. 55,showing the frequency allocations versus the frequency axis 551. Thefrequency band 552, ranging from 5 MHz to 40 MHz, is reserved for a CATVreturn channel or the DOCSIS (Data Over Cable Service InterfaceSpecification) service. The video channels are carried as a broadcastservice using 6 MHz channels spaced from 50 MHz up to 860 MHz.

Carrying the shifted wireless signal over a CATV service carryingcoaxial cable, involving the example of a single 22 MHz IEEE802.11channel, may use three distinct frequency bands. In one embodiment, partor all of the DOCSIS/return channel 552 is used for carrying the shiftedwireless signal. Yet in another embodiment, four adjacent 6 MHz channelsin the video distribution band 553 are vacated from the video contentthus creating a single 24 MHz (4 times 6 MHz) channel that may carry theshifted wireless signal. However, employing the above CATV bands mayresult in service degradation. In another embodiment, the shiftedwireless signal is carried in a band above 860 MHz, hence notoverlapping with the other CATV service signals over the coaxial cable.Using any of the above frequency bands for the shifted wireless signaltypically involves a Band Pass Filter 561 passing the frequency bandallocated for carrying the shifted wireless signal and substantiallyrejecting the other CATV-related signals carried simultaneously over thesame cable. Similarly, a single BPF 562 may be used for passing the CATVsignals and substantially stopping the band allocated for the shiftedwireless signal. The BPFs 561 and 562 may each be implemented as LPF oras HPF, depending upon the location of the respective bands.

System 560 in FIG. 56 describes a coaxial cable 568 based network, whichis based on the above system 380 in FIG. 38 adapted for CATV rather thana telephone environment. Coaxial cable 568 serves as the wiring medium(substituting telephone wire pair 382 above). The HPFs 385 a and 385 bof system 380 are respectively replaced with BPFs 561 a and 561 b, whichare designed to pass only the frequency band allocated for the shiftedwireless signal. Similarly, LPFs 383 a and 383 b shown as part of system380 and oriented for passing the analog telephone signal arerespectively substituted with BPFs 562 a and 562 b. The telephoneconnectors 388 are replaced with CATV related connectors 564, commonlyF-Type, BNC, and similar RF connectors. Access to the CATV servicesignals over the coaxial cable 568 is achieved via CATV units 566 a and566 b, wherein each may be a DOCSIS Cable Modem, set-top-box or anyother equipment commonly used in conjunction with CATV services.Television sets 567 a and 567 b are shown as respectively connected tothe CATV units 562 a and 562 b, representing CATV end units such astelevision sets and personal computers or any other video receiver.

In a similar way, all above systems may be adapted to use coaxial cable568 as a substitute to the telephone wire pair 382 or to any other wiredmedium. The filter 385 is substituted with filter 561 and filter 383 issubstituted with filter 562. Similarly, a coaxial connector 564 isrequired instead of the telephone connector 388 described above. Similarto the above discussion regarding housing of shifter 210, and connectedfunctions and circuits may be embedded (in part or in full) in a CATVoutlet or in a nodule mechanically and electricallyattachable/detachable to a CATV outlet.

AC Power.

While the invention was exemplified above with regard to using aPOTS-oriented telephone wire pair 382 and with regard to carrying aPOTS-oriented analog telephone signal 391, as well as with regard to acoaxial cable 568 carrying a CATV service signals, it is apparent thatother wiring type as well as carrying other service signals may beequally used. In one or more embodiments according to the presentinvention, the power wiring used to distribute AC power as part of thepower grid is used as the conductive medium. The superior communicationcharacteristics of the wireless signals, which are retained while beingfrequency shifted, result in a communication path even over such powerwiring that was primarily installed to carry high AC power signals. Inone or more embodiments according to the present invention, alow-voltage wiring is involved, while carrying 110 VAC/60 Hz AC powersignal as is common in North America, or 240 VAC/50 Hz as is common inEurope.

System 570 shown in FIG. 57 is conceptually similar to system 380 shownin FIG. 38, however adapted to use AC power wire pair (commonly referredto as powerline) 573 instead of the telephone wire pair 382. The shiftedwireless signal is coupled to and from the AC wire pair 573 through aHPFs 572 a and 572 b. HPF 572 is designed to pass the shifted wirelesssignal and to substantially block the AC power related signals, whichinclude its harmonics, spurious and other signals which may exist overthe power wire pair 573. Receiving the AC power signal from the powerpair 573 involves using a LPF 571. The LPF 571 passes the AC powersignal, while rejecting signals in the shifted wireless signal frequencyband. The LPF 571 also serves to block noises and other unwanted signalsto be inserted to the powerlines. System 570 shows two locations 575 aand 575 b both connected to communicate and be powered from thepowerline 573. The AC power signal received after being filtered by LPF571 is used to feed an AC/DC power supply 453, which DC power output maybe used to power the location power consuming elements such as shifter210 via DC power bus or connection 457. The filtered AC signal may alsobe connected to any AC-powered appliance 576 a, via common AC power plug577 b and AC power jack 577 a. Similarly, The filtered AC signal mayalso be connected to any AC-powered appliance 576 b, via common AC powerplug 577 d and AC power jack 577 c. System 580 shown in FIG. 58 issimilar to system 400 shown in FIG. 40 above, however adapted to usepowerline segments 573 a, 573 b, and 573 c connected is a ‘star’topology. Similarly, systems 590 and 600 (shown in the respective FIGS.59 and 60) are based on the respective systems 410 and 415 (shown inFIGS. 41 and 41 a respectively).

In the case wherein the AC power wire pair 573 is an in-building wiringaccessed via a common AC power outlet, the device such as 575 a (FIG.57) or any device including part or all of the components connected orcoupled to the powerline 573 may be enclosed in plug-in form asdescribed above. Such plug-in unit 610 is shown is perspective view inFIG. 61 a, also showing a typical North-American type AC power outlet191 is shown, having two power sockets 192 a and 192 b. Front view andrear view of the plug-in unit 610 are respectively shown in FIGS. 61 band 61 c. The device 575 a (FIG. 57), for example, or any other deviceincluding the frequency shifter 210, is enclosed as plug-in module 610shown to have two power prongs 193 a and 193 b (FIG. 61 c) respectivelymating with sockets 192 a and 192 b, providing electrical connection(for both receiving AC power and communication using thefrequency-shifted wireless signal) as well as mechanical support,enabling the plug-in unit 610 to be easily attached to the outlet 191.Antenna 52 a is shown, as well as a channel selecting mechanical rotaryswitch 139 a having 11 positions for selecting one out of the 11channels of the IEEE982.11g. In the example shown, rotary switch 139 bis set to channel 6.

Similar to the above mentioned, the wired medium 201, being either ageneral twisted-pair, a telephone wire pair 382, AC power wiring 573, orcoaxial cable 568 may be used for coupling the WLANs, (W)PANs, (W)MANs(Metropolitan area Network) such as HIPERMAN or WiMAX, and may be basedon IEEE 802.16, or any wireless WAN (Wide Area Network).

Similar to that discussed above, attenuators may be inserted in eitherthe radio receive path, the transmit path or both, as described abovewith regard to sub-system ‘A’ of systems 130 b and 130 c, in order toovercome part or all of the above described disadvantages.

Wireless units include any devices which use non-conductive medium forreceiving of transmitting (or both) information, being analog or digitalinformation. By way of example, wireless units may encompass mobileunits such as laptop computers, handheld remote controls and PersonalDigital Assistants (PDA) as well as any other wireless-enabled handhelddevices such as cellular telephone handset and cordless telephone sets.

The frequency shifters 120 and 210 (as well as system 260) have beendescribed above as a physical layer supporting only devices, whereinhigher OSI layers such as protocol converting or format changing do nottake place along the signal path. It is apparent that functions such asprotocol converting and other higher OSI layers handling may be addedanywhere along the signal path.

The systems and network according to the invention may be used outdoorsto allow increased free-air propagation coverage, or may be used indoorsto allow wireless communication between rooms and floors in a building.Similarly, the arrangements may allow for communication betweenbuildings. Furthermore, the methods described may be used to allowbridging between outdoor and indoor communication. In the latter caseand in other embodiments, part of the system may be housed in the NID orbe attached to the external wall of a building.

While the invention has been exampled above with regard to usingstandard IEEE 802.11g technology, signals and components, it will beappreciated that the invention equally applies to any other wirelessbased technology, using either single or multi carrier signals forimplementing either spread spectrum or narrowband, using eitherunlicensed bands (such as ISM) or licensed spectrum. Such technology maybe part of the IEEE 802.11 (such as IEEE is 802.11b or IEEE 802.11a),ETSI HiperLAN/2, or any technology used for WLAN, home networking or PAN(Personal Area Network). One non-limiting example is using IEEE 802.11bbased on CCK (Complementary Code Keying). Other non-limiting examplesare Bluetooth™, ZigBee, UWB, and HomeRF™. Furthermore, WAN (Wide AreaNetwork) and other wireless technologies may be equally used, such ascellular technologies (e.g., GSM, GPRS, 2.5G, 3G, UMTS, DCS, PCS andCDMA) and Local Loop oriented technologies (WLL—Wireless Local Loop)such as WiMAX, WCDMA, and other Fixed Wireless technologies, includingmicrowave based. Similarly, satellite based technologies and componentsmay be equally used. While the technologies mentioned above are allstandards-based, proprietary, and non-standards technologies may beequally used according to present invention. Furthermore, the inventionmay equally apply to using technologies and components used in non-radiobased through-the-air wireless systems such light (e.g. infrared) oraudio (e.g., ultrasonic) based communication systems.

The frequency shifters 120 and 210 (as well as system 260) have beendescribed above as using I/Q demodulating and modulating as described insystems 110 and 120 above. It is apparent that such frequency shiftersin all above systems may equally use any frequency-shifting scheme, suchas mixer/filter, heterodyne or super-heterodyne, or any other frequencyshifting scheme known in the art. In particular, any frequency shiftingscheme which does not require encoding and decoding of the digital datacarried by the wireless signal or any scheme involving digital dataprocessing may be equally used.

The invention has been described above referring to using a wirelessbackbone (such a system 150) or using a wired medium (such as systems220 and 230) for carrying a wireless signal over a wireless band toanother location, in which the wireless signal is reconstructed andrestored to the same wireless signal over the same band. However, theinvention may be equally applied to any arrangement wherein thedifferent frequency band (such as different channels) are used, whereinthe system also serves to shift the wireless signal from one band in onelocation to another band (such as another channel) in another location.

Similarly, the system may use a cellular communication as the wirelessbackbone. By way of example, wireless communication link 152 b formingcoverage area 151 b may use cellular networking, either as a dedicatedlink or as part of a cellular network. Alternately, a wired backbonesuch as 201 may be used in order to interconnect cellular coverage arearepresented by the links 152 a and 152 b in system 220 shown in FIG. 22above. The cellular technology used in both cases may be analog ordigital. Such digital technologies include GSM (Global System for MobileCommunications), GPRS (General Packet Radio Service), CDMA (CodeDivision Multiple Access), EDGE (Enhanced Data Rates for GSM Evolution),3GSM, DECT (Digital Enhanced Cordless Telecommunications), Digital AMPS(per IS-136/TDMA, for example) and iDEN (Integrated Digital EnhancedNetwork). The service carried over the cellular network may be voice,video or digital data such as the recently introduced EVDO (EvolutionData Only).

In one preferred embodiment according to the invention, isolated orseparated areas using short-range wireless technology are connectedusing wired or wireless medium having a longer range. For example, twoor more non-overlapping PAN or WPAN networks may be interconnected by abackbone (either wired or wireless) using either LAN or WLAN schemes.Similarly, two or more non-overlapping LAN or WLAN networks may beinterconnected by a backbone (either wired or wireless) using either WANor MAN schemes. In another preferred embodiment according to theinvention, isolated or separated areas are interconnected using LOScommunication (such as light or electromagnetic transmission usingspectrum above 3 GHz. Similarly, isolated or separated areas using LOSfor communication within the location may be interconnected usingnon-LOS communication means.

Non-wired Medium.

The invention has been described above referring to one or more wirelesscommunication links 152 using radiation of electromagnetic waves orradio signals propagating over the air. However, the invention may beequally applied to any other types of non-conductive or through-the-aircommunication mediums, technologies, and frequencies. Using thealternatives for radio-based communication described herein may be asubstitute for a single wireless communication link 152. In the casewherein two or more such wireless communication links are described,such as links 152 a, 152 b and 152 c in system 150 shown in FIG. 15,one, two or all of the links may be substituted.

In one embodiment according to the invention the non-conductive andthrough the air communication makes use of light as the communicationsignal. Light may be considered as electromagnetic transmission usingthe very high electromagnetic spectrum. The systems may use a humanvisible light or non-visible light such as IR (Infra-Red) or UV(Ultra-Violet). Employing light communication will contemplate the useof light transmitters such as LED (Light Emitting Diode) and laserdiodes, and light receivers or sensors such as photo-diodes, as asubstitute to the antenna 52, and part or all of the connectedcomponents and functions. Typically light based communication is basedon Line-Of-Sight (LOS), and using the above-described embodiments mayenable proper accommodating with the LOS limitation.

In one embodiment according to the invention the non-conductive mediumis based on a wave-guide and not based on free air propagation. Anexample may be a fiber-optic medium. In such configuration the antenna52 is replaced with a fiber-optic connector, added to laser diode fortransmitting to the medium and photo-diode or photo-cell for receivingfrom the medium.

Similarly, a sound or an audio-based communication through the air maybe used as a substitute to the electromagnetic waves based communicationdescribed above. The communication link may use audible sound (typically20-20,000 Hz), inaudible sound (ultrasonic, above 20,000 Hz) andinfrasonic (below 20 Hz). In this case, the antenna 52 will besubstituted with a microphone or a similar device converting the soundsignal into an electrical signal, and a speaker or a similar device forgenerating the audio signal and transmitting it to the air. A transducercombining into a single device both the speaker and the microphonefunctionalities may as well be used.

While the invention has been described with regard to IEEE802.11gwireless signals and systems carrying digital data, it will beappreciated that the invention equally applies to other embodimentswherein the wireless signals (and system) are used to carry analogsignals. One non-limiting example involves cordless telephony. Cordlesstelephones are known to carry telephone (and control) signals over theair using ISM bands.

While the invention has been exampled above with regard to usingstandard IEEE 802.11g technology, signals and components, it will beappreciated that the invention equally applies to any other wirelessbased technology, using either single or multi carrier signals forimplementing either spread spectrum or narrowband, using eitherunlicensed bands (such as ISM) or licensed spectrum. Such technology maybe part of the IEEE 802.11 (such as IEEE 802.11b or IEEE 802.11a), ETSIHiperLAN/2 or any technology used for WLAN, home networking or PAN(Personal Area Network). One non-limiting example is using IEEE 802.11bbased on CCK (Complementary Code Keying). Other non-limiting examplesare BlueTooth™, ZigBee, UWB and HomeRF™. Furthermore, WAN (Wide AreaNetwork) and other wireless technologies may be used, such as cellulartechnologies (e.g., GSM, GPRS, 2.5G, 3G, UMTS, DCS, PCS and CDMA) andLocal Loop oriented technologies (WLL—Wireless Local Loop) such asWiMax, WCDMA and other Fixed Wireless technologies, including microwavebased technologies. Similarly, satellite based technologies andcomponents may be equally used. While the technologies mentioned aboveare all standards-based, proprietary and non-standards technologies maybe equally used according to present invention. Furthermore, theinvention may equally apply to using technologies and components used innon-radio based through-the-air wireless systems such as light (e.g.,infrared) or audio (e.g., ultrasonic) based communication systems.

While the invention has been exampled above with regard to usingstandard IEEE 802.11g technology wherein packets are communicated overthe wireless medium, it will be appreciated that the invention equallyapplies to a continuous signal, being digital or analog. By way ofexample, the invention may apply to a cordless telephone system,allowing for the base-unit and the mobile handset to be distant fromeach other but yet to offer a proper wireless communication betweenthem.

Housing.

A location according to the invention typically includes a frequencyshifter 120 bridging between two wireless signals or a frequency shifter210 bridging between wireless and wired signals. Similarly, system 260above was shown as bridging between two wired signals. Such a locationalso includes all the functions conductively coupled to the frequencyshifter 120 or 210 (as well as system 260). Such added functions mayinvolve powering, and carrying additional service signals such as CATVand telephone signal. A device including all or part of the frequencyshifter and other connected circuits and functions may be enclosed orhoused and/or integrated within an enclosure (in part of in full) aswarranted by the application. In some embodiments, the device will behoused as a distinct, separately packaged and stand-alone device. Suchsingle enclosure may be a stand-alone unit, which may be configured as adesktop or wall mounted unit. In some embodiments, the device may beintegrated with connected equipment or coupled equipment such as a WLANunit or a data unit. In the cases wherein such a device is to be used inan outdoor environment, commonly a hardened mechanical design is to becontemplated.

In many scenarios the device is used in a building environment(in-door). Since in most cases the device couples wirelessly with WLANunits (such as WAP and clients) it may be advantageous to wall mount thedevice in order to save desk space and avoid non-aesthetic and non-safecabling. In particular, mounting the device in a ceiling or over a wallmay be required in order to get optimum wireless coverage in the site.

According to one aspect of the invention in-wall hidden power carryingconductors or wire-pairs are used to power the device. Such cabling maycontain AC power wiring or other wirings that were primarily installedand used for carrying power, such as in-vehicle power carryingconductors. Alternatively, power may be carried over wirings orientedtoward carrying analog service signals or digital data signals. Forexample, LAN cables carrying PoE (e.g., as per IEEE802.3af) or atelephone wire pair carrying a power signal may be contemplated. Anexample of a scheme for carrying AC power over a telephone wire pairwith a telephone signal is described in the '353 patent.

According to one aspect of the invention in-wall hidden wire pairs maycomprise telephone, AC power, or CATV wiring infrastructure. The wirepair may be carrying service signals (such as telephone, AC power orCATV signals), and may be accessed via outlets (such as telephone, ACpower or CATV outlets).

In the above cases of connecting to in-wall wirings through an outlet,it may be contemplated to enclose the device as a single enclosure thatplugs into the appropriate outlet, for receiving or inserting powerthereto and/or for coupling to the service signal and/or for couplingthe shifted wireless signal thereto. Such plug-in modules are known inthe art to include a dedicated modem (such a powerline modem ortelephone line modem), however are not disclosed to include a frequencyshifting function. The plug-in device may be simply plugged in to theoutlet, sometimes referred to as ‘wall-wart’ (supported only by themating connectors), or may be contemplated to include a mechanicalfastening means in order to enable reliable and secured mechanicalattachment to the outlet and to allow reliable and secured connecting tothe plug-in module. Patent Application '0561 suggests multiple designsof such a plug-in unit, which are all applicable to a device accordingto the present invention. In one or more embodiments, the medium modem254 in Patent Application '0561 is to be substituted with the frequencyshifter 210 (or 120 or 260) described above.

Outlets in general (to include LAN structured wiring, electrical poweroutlets, telephone outlets, and cable television outlets) havetraditionally evolved as passive devices being part of the wiring systemhouse infrastructure and solely serving the purpose of providing accessto the in-wall wiring. However, there is a trend toward embedding activecircuitry in the outlet in order to use them as part of the home/officenetwork, and typically to provide a standard data communicationinterface. In most cases, the circuits added serve the purpose of addingdata interface connectivity to the outlet, added to its basic passiveconnectivity function.

An outlet supporting both telephony and data interfaces for use withtelephone wiring is disclosed in U.S. Pat. No. 6,549,616 entitled‘Telephone outlet for implementing a local area network over telephonelines and a local area network using such outlets’ to Binder. Anothertelephone outlet is described in U.S. Pat. No. 6,216,160 to Dichter,entitled ‘Automatically configurable computer network’. An example ofhome networking over CATV coaxial cables using outlets is described inUS Patent Application Publication 2002/0194383 to Cohen et al. entitled:‘Cahleran Networking over Coaxial Cables’ to Cohen et al. Such outletsare available as part of HomeRAN™ system from TMT Ltd. of Jerusalem,Israel. Outlets for use in conjunction with wiring carrying telephony,data and entertainment signals are disclosed in US Patent ApplicationPublication 2003/0099228 to Alcock entitled ‘Local area and multimedianetwork using radio frequency and coaxial cable’. Outlets for use withcombined data and power using powerlines are described in US PatentApplication Publication 2003/0062990 to Schaeffer et al entitled‘Powerline bridge apparatus’. Such power outlets are available as partof PlugLAN™ by Asoka USA Corporation of San Carlos, Calif. USA.

While the active outlets have been described above with regard tonetworks formed over wiring used for basic services (e.g., telephone,CATV and power), it will be appreciated that the invention can beequally applied to outlets used in networks using dedicated wiring. Insuch a case, the outlet circuitry is used to provide additionalinterfaces to an outlet, beyond the basic service of single dataconnectivity interface. As a non-limiting example, it may be used toprovide multiple data interfaces wherein the wiring supports single suchdata connection. An example of such an outlet is the Network Jack™product family manufactured by 3Com™ of Santa Clara, Calif., U.S.A. Inaddition, such outlets are described in U.S. Pat. No. 6,108,331 toThompson entitled ‘Single Medium Wiring Scheme for Multiple SignalDistribution in Building and Access Port Therefor’ as well as U.S.Patent Application 2003/0112965 Published Jun. 19, 2003 to McNamara etal. entitled ‘Active Wall Outlet’.

According to one aspect of the invention, part or all of a device in alocation is enclosed as an outlet. In this case, the single enclosure isconstructed to be in a form identical or substantially similar to thatof a standard outlet or having a shape allowing direct mounting in anoutlet receptacle or opening. Such an enclosure may be in the form tofully or in part substitute for a standard outlet, and may include wallmounting elements substantially similar to those of a standard walloutlet. Patent Application '0954 suggests multiple designs of suchoutlets including electronic circuitry, which are all applicable of adevice according to the present invention. In one or more embodiments,the medium modem 54 in Patent Application '0954 is to be substitutedwith the frequency shifter 210 (or 120 or 260) described above.

Those of skill in the art will understand that the various illustrativelogical blocks, modules and circuits described in connection with theembodiments disclosed herein may be implemented in any number of waysincluding electronic hardware, computer software, or combinations ofboth. The various illustrative components, blocks, modules and circuitshave been described generally in terms of their functionality. Whetherthe functionality is implemented as hardware or software depends uponthe particular application and design constraints imposed on the overallsystem. Skilled artisans recognize the interchangeability of hardwareand software under these circumstances, and how best to implement thedescribed functionality for each particular application.

Although exemplary embodiments of the present invention have beendescribed, this should not be construed to limit the scope of theappended claims. Those skilled in the art will understand thatmodifications may be made to the described embodiments. Moreover, tothose skilled in the various arts, the invention itself herein willsuggest solutions to other tasks and adaptations for other applications.It is therefore desired that the present embodiments be considered inall respects as illustrative and not restrictive, reference being madeto the appended claims rather than the foregoing description to indicatethe scope of the invention.

It will be appreciated that the aforementioned features and advantagesare presented solely by way of example. Accordingly, the foregoingshould not be construed or interpreted to constitute, in any way, anexhaustive enumeration of features and advantages of embodiments of thepresent invention.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects as illustrative and notrestrictive. The scope of the invention is, therefore, indicated by theappended claims rather than by the foregoing description. All changeswhich come within the meaning and range of equivalency of the claims areto be embraced within their scope.

Public Notice Regarding the Scope of the Invention and Claims

While the invention has been described in terms of preferred embodimentsand generally associated methods, the inventor contemplates thatalterations and permutations of the preferred embodiments and methodswill become apparent to those skilled in the art upon a reading of thespecification and a study of the drawings.

Accordingly, neither the above description of preferred exemplaryembodiments nor the abstract defines or constrains the invention.Rather, the issued claims variously define the invention. Each variationof the invention is limited only by the recited limitations of itsrespective claim, and equivalents thereof, without limitation by otherterms not present in the claim. In addition, aspects of the inventionare particularly pointed out in the claims using terminology that theinventor regards as having its broadest reasonable interpretation; themore specific interpretations of 35 U.S.C. section 112 (6) are onlyintended in those instances where the term “means” is actually recited.The words “comprising,” “including,” and “having” are intended asopen-ended terminology, with the same meaning as if the phrase “atleast” were appended after each instance thereof.

1. A network for wireless communication of a wireless signal in awireless frequency band between at least one first wireless unit and aplurality of second wireless units, said network comprising: a pluralityof distinct wired mediums for interconnecting the first and secondwireless units, the wired mediums providing a wired frequency banddistinct from, and lower in frequency than, the wireless frequency band,each wired medium having first and second ends; a center device coupledto the at least one first wireless unit and connected to the first endof each of the wired mediums, said center device being operative tofrequency shift the wireless signal between the wireless frequency bandand the wired frequency band, and said center device being furtheroperative to couple the at least one first wireless unit to each of saidwired mediums; and a plurality of remote devices, each connected to asecond end of a respective one of said wired mediums and each coupled toa respective one of the plurality of second wireless units, each of saidremote devices being operative to frequency shift a signal between thewireless frequency band and the wired frequency band, wherein: saidnetwork is operative to allow said center device to receive the wirelesssignal in the wireless band from the at least one first wireless unit,to down frequency shift the wireless signal to the wired frequency band,and to transmit the shifted wireless signal to all connected wiredmediums; each of said remote devices is operative to up frequency shiftthe shifted wireless signal from said center device to the wirelessfrequency band, to reconstruct the wireless signal, and to transmit thereconstructed wireless signal to the respective one of the plurality ofsecond wireless units; said network is operative to allow one of saidremote devices to receive a wireless signal in the wireless band fromthe one of the plurality of second wireless units coupled thereto, todown frequency shift the received wireless signal to the wired frequencyband, and to transmit the shifted wireless signal to the connected wiredmedium; and said center device is operative to up frequency shift thereceived shifted wireless signal to the wireless frequency band toreconstruct the wireless signal, and to transmit the reconstructed firstwireless signal to the at least one first wireless unit.
 2. The networkaccording to claim 1, wherein at least one of said remote devicescomprises a frequency shifter that is based on a heterodyne circuit. 3.The network according to claim 1, wherein at least one of said remotedevices comprises a frequency shifter, said frequency shiftercomprising: an I/Q demodulator coupled to receive the wireless signal,for providing the I and Q component signals of the wireless signal; anI/Q modulator coupled to receive the first wireless signal I and Qcomponent signals, said first I/Q modulator being operative toreconstruct the wireless signal frequency shifted to the wired frequencyband.
 4. The network according to claim 3, wherein said I/Q modulatorand said I/Q demodulator are part of a wireless transceiver component.5. The network according to claim 1, wherein the wireless signal is aspread-spectrum signal.
 6. The network according to claim 1, wherein thefirst wireless signal is a multi-carrier signal based on one of OFDM,DMT and CDMA modulations.
 7. The network according to claim 1, whereinthe wireless frequency band is selectable from a plurality of adjacentfrequency bands.
 8. The network according to claim 7, wherein thewireless frequency band is selected by a switch.
 9. The networkaccording to claim 1, wherein the wireless signal conforms to at leastone of the following standards: WPAN, WLAN, WMAN, WAN, BWA, LMDS, MMDS,WiMAX, HIPERMAN, IEEE802.16, Bluetooth, IEEE802.15, UWB, ZigBee,cellular, IEEE802.11 standards, OSM, GPRS, 2.5G, 3G, UMTS, DCS, PCS andCDMA.
 10. The network according to claim 1, wherein the wirelessfrequency band is an ISM frequency band.
 11. The network according toclaim 1, wherein at least part of one of the wired mediums compriseswiring in a wall.
 12. The network according to claim 1, wherein one outof said remote devices is enclosed in a single enclosure that is wallmountable.
 13. The network according to claim 12, wherein the singleenclosure is shaped to plug into an outlet.
 14. The network according toclaim 12, wherein the single enclosure is further shaped to mechanicallyattach and electrically connect to an outlet.
 15. The network accordingto claim 12, wherein the single enclosure is constructed to have atleast one of the following: a form substantially similar to that of astandard outlet; wall-mounting elements substantially similar to thoseof a standard wall outlet; a shape allowing direct mounting in an outletopening or cavity; and a form to at least in part substitute for astandard outlet.
 16. The network according to claim 1, wherein thewireless signal is transmitted in the wireless frequency band in one ofa WPAN, WLAN, MAN and WAN network.
 17. The network according to claim 1,wherein at least one of the wired mediums is one of: a twisted wirepair; UTP; STP; a telephone wire pair; AC power wires; a coaxial cable,and a LAN cable.
 18. The network according to claim 1, wherein at leastone part of one of the wired mediums is in a building and at leastanother part the one of the wired mediums is external to the building.19. The network according to claim 1 having a point-to-point topology,wherein at least one of the wired mediums is a single wiring havingexactly two ends, said center device is connected to one of the ends ofthe single wiring and one of said remote devices is connected to theother end of the single wiring.
 20. The network according to claim 1,wherein at least one of the wired mediums has a bus, star, tree, orpoint-to-multipoint topology.
 21. The network according to claim 1,wherein: at least one of the wired mediums is connected to carry a DC orAC power signal using FDM; the power signal is carried in a frequencyband distinct from the wired frequency band; and at least one of saiddevices is coupled to be powered by the power signal.
 22. The networkaccording to claim 1, wherein: at least one of the wired mediums isconnected to carry a first signal using FDM; the first signal is carriedin a frequency band distinct from the wired frequency band; and thefirst signal is one of an analog telephone signal and a CATV-relatedsignal.
 23. The network according to claim 1, wherein said center deviceis conductively coupled to the wireless unit.
 24. The network accordingto claim 1, wherein at least one of said remote devices is conductivelycoupled to the distinct wireless unit.
 25. The network of claim 1,wherein at least one of said remote devices is powered by a power signalcarried over at least one of said wired mediums in addition to signalsin the wired frequency band carried by said at least one of said wiredmediums, using a distinct frequency band, and further comprising afilter coupling said at least one of said remote devices to said atleast one of said wired mediums.
 26. The network of claim 1, wherein atleast one of said wired mediums is connected to concurrently carryanalog or digital signals in a distinct frequency band included in thewired frequency band, and wherein the shifted wireless signal is shiftedto a portion of the wired frequency band that is separate from thedistinct frequency band of the analog or digital signals.